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While existing research has explored control strategies in multi-dimensional fields, the interconnectedness between electromagnetic and vibrational fields remains relatively uncharted. To explore this intersection and harness its potential, we propose an intelligent programmable metasurface that modulates electromagnetic fields based on vibration intensity information. This paper introduces a groundbreaking approach that synergizes the physical fields of mechanical (vibrational) waves with electromagnetic waves, facilitating the detection and manipulation of information from both fields. By combining a programmable metasurface, vibration sensors, and microcontroller units, we have achieved regulation of the electromagnetic field through utilization of vibration intensity information. In this work, we have introduced six coding patterns that facilitate dual-beam scanning with variable deflection angles. A 20 × 20 metasurface is fabricated and measured, and the measured results are in good agreement with the simulated results. This research opens a new avenue for manipulating electromagnetic waves. Furthermore, the findings have the potential to impact a wide range of fields, including building structuralhealth monitoring, industrial production, mechanical equipment monitoring, and earthquake monitoring. [ABSTRACT FROM AUTHOR]

Instability is one of the major failure modes of long span arch bridges, and its possibility of occurrence will be increased as triggered by earthquake excitations. However, the randomness of each ground motion causes the difficulty in achieving a reliable assessment of the safety of the bridges in regard to its stability issue based on certain time history analysis. Therefore, a failure probability-based instability evaluation method and corresponding instability damage index are proposed in this study to solve this problem, converting the deterministic analysis of a ground motion into a probability analysis of a group of random ground motions. The results find that the input direction, the velocity pulse and the pulse period of the ground motion have a significant impact on the stability of the bridge, while seismic moment and PGV/PGA ratio do not. The fragility curves show that the bridge has more than 60% probability of slight instability when input PGA reaches 0.2 g, 50% probability of moderate instability when input PGA reaches 0.6 g, and 20% probability of collapse when input PGA reaches 1.0 g. Moreover, when the PGA approaches 1.0 g, it is discovered that the velocity pulse and the pulse period can increase the chance of the occurrence of bridge instability by 20%–30%. [ABSTRACT FROM AUTHOR]

Timely estimation of earthquake magnitude plays a crucial role in the early warning systems for earthquakes. Despite the inherent danger associated with earthquake energy, earthquake research necessitates extensive parameter estimation and predictive techniques to account for uncertain trends in earthquake waveforms when determining earthquake magnitudes using a single station. This study introduces an effective solution to tackle the issue through the automatic magnitude deep network (AMagDN) model. The proposed model includes long short-term memory (LSTM), a bidirectional LSTM, an autocorrelation attention mechanism, and a machine learning block that can capture detailed information from the seismic waveform recorded during an earthquake. The unique feature of this model is the use of multivariate time series waveforms derived from recorded accelerograms specifically tailored to their energy significance with magnitude and seven fusion tabular parameters involving source and geospatial features. The proposed model's training, validation and testing are done using independent 15014, 1287 and 3448 records maintained by the Kyoshin network, Japan, for moderate to great impact earthquakes between 5.5 and 8.0 ( M JMA ). A comparative study shows that the proposed model outperforms recent state-of-the-art models and common linear relations, reducing mean absolute prediction error by 40% from the second-best model. The multi-stations data are also used for successfully forecasting the magnitudes of two significant earthquakes of 7.7 and 7.3 magnitude ( M JMA ) using the proposed model. The reliable prediction capabilities of the proposed model for both single and multi-station data clearly demonstrate its utility in reducing earthquake hazards. [ABSTRACT FROM AUTHOR]

The tsunami that was triggered by the 2024 Noto Peninsula Earthquake caused severe inundation along the coast on the northeastern tip of the peninsula, propagated over the sea with rough wind waves, and reached the coast and rivers located away from the peninsula. This manuscript presents the results of a field survey and a supplementary analysis for investigating the tsunami characteristics away from the peninsula where rough wind waves had a significant influence on the tsunami behavior. Video images captured by closed-circuit television (CCTV) cameras were used for onsite detection of the tsunami traces and for extracting time-varying water level profiles. Wind waves had little influence on the tsunamis along the lower reaches of the rivers, and the measured tsunami heights were consistent with each other in the nearby field. At most of the survey sites, the highest tsunami traces were created not by the first but by the following tsunami. Along Toyama Bay, the tsunami water levels first decreased within several minutes after the earthquake, and the arrival times for this negative tsunami peak was earlier in the southern part of the bay. These characteristics may indicate the existence of multiple tsunami sources inside Toyama Bay. [ABSTRACT FROM AUTHOR]

On January 1 2024, at 16:10 JST, an earthquake of Mw 7.5 occurred underneath the Noto Peninsula of Ishikawa Prefecture, Japan. This event caused a cascading disaster impact on cities in the Noto Peninsula through a series of strong earthquake shakes, strong ground motions, slope failures, liquefaction, fire, and tsunamis. The tsunami first reached Suzu City a few minutes after the earthquake, eventually affecting approximately 340 km of the coast from the Ishikawa to Niigata Prefectures. The Coastal Engineering Committee of the Japan Society of Civil Engineers conducted an organized post-event field survey to understand the impact of tsunamis on land. This study summarizes the post-event field survey results and provides a general understanding of tsunami behavior and damage using measured tsunami inundation and run-up heights. [ABSTRACT FROM AUTHOR]

Background Earthquakes disproportionately affect women and exacerbate gender and social inequalities. This study aims to investigate the psychological impact of the earthquake in Türkiye on women and the associated factors. Methods This is a survey-based study. We collected data from 498 women residing in cities most affected by the earthquake. Results Participants' mean age was 27.72 ± 5.4. Over 78% of the participants lost at least one family member, and 43.7% lost at least one child due to the earthquake. The mean average of Brief Symptom Inventory (BSI) scores was 100.8 (SD = 8.37), and the Global Severity Index was 1.9 (SD = 0.16). Regression analysis showed that higher education levels predicted poor outcomes across most BSI dimensions. Losing a family member and shelter and injury status were also predictors for several mental health outcomes of the BSI subscales. Conclusions Earthquakes significantly impact women's well-being and may have a broader impact on the whole family. There is an urgent need to provide psycho-social interventions in the response and recovery phases of the crisis to meet the affected women's needs. This includes providing basic needs with attention to women-specific needs, restoring social networks, addressing gender-based violence and providing gender-sensitive specialized interventions for those who need further support. [ABSTRACT FROM AUTHOR]

As electric vehicle (EV) adoption increases, transportation services will shift dependence from liquid fuel infrastructure to electric power infrastructure. Since transportation plays a major role in disaster response and recovery, this shift in dependence has important implications for coupling electrical grids and transport resilience. The implications for the electrical grid for southwestern British Columbia, Canada are examined, motivated by this region's high EV adoption rate and the potential for a catastrophic magnitude 9.5 earthquake. A comparison of the resilience of the electrical infrastructure compared to the fuel infrastructure is provided and approaches for increasing resilience in the region for EV power supply are discussed. This paper compiles lessons learned from past large earthquakes in Chile, Japan, and New Zealand with consideration given to successes and failures. While this paper was written with a focus on southwestern British Columbia, many of the suggestions for increasing power system resilience could be applied in other seismically active locations during the transition to EVs. This paper also considers integrated disaster resilience planning for the changing transport landscape from fuel vehicles to EVs. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to explore the impact of psychological stress on erectile dysfunction (ED) in male patients following the Gaziantep-Kahramanmaras earthquake. The investigation aimed to establish correlations between earthquake-induced stress and changes in sexual function using International Index of Erectile Function (IIEF), Patient Health Questionnaire-9 (PHQ-9), and Generalized Anxiety Disorder-7 (GAD-7) scores. Materials and Methods: A retrospective analysis was conducted on male ED patients from a Gaziantep urology clinic post-earthquake (March to August 2023). Patients with deteriorated erectile function post-earthquake (group 1) and those with pre-existing ED experiencing worsened symptoms post-earthquake (group 2) were included. Data collected encompassed sexual histories, IIEF scores, laboratory tests, and PHQ-9/GAD-7 evaluations. Patients were also evaluated mild and mild to moderate ED, moderate and severe ED according to IIEF erectile function. Results: Seventy-six patients were evaluated (24 in group 1 and 52 in group 2). Significant reductions in total IIEF scores (58 to 40 in group 1 and 49 to 33 in group 2) were observed post-earthquake in both groups (p<0.001). PHQ-9/GAD-7 scores was 11.12±3.79/9.34±3.11 in mild and mild to moderate ED and 13.17±3.05/12.14±3.17 in moderate and severe ED (p=0.011, p<0.001, respectively). Negative correlations existed between PHQ-9/GAD-7 scores and IIEF erectile function (p<0.05) and total IIEF (p<0.05). Conclusions: This research suggests a plausible connection between the Gaziantep-Kahramanmaras earthquake and heightened ED cases. Psychological stress post-earthquake may contribute to worsened ED symptoms. Further investigations are warranted to comprehensively understand the interplay between natural disasters and sexual dysfunction, essential for optimizing patient care in challenging situations. [ABSTRACT FROM AUTHOR]

North-Eastern (NE), India and its adjoining region is one of the sixth most seismically active regions of the world. In the present investigation, the return period of earthquake and probability of occurrence inferred from Gutenberg–Richter (GR) relation was estimated for NE, India region and its vicinity. When we consider the entire NE, India region and its vicinity, it evidently suggested that the return period of earthquakes of 7 ≤ Mw ≤ 8.6 is short, which ranges from 32.73 to 162.59 years. It was observed that the earthquake occurrence from infinitesimally short interval t~0 for Mw~3.6–4 is embedded with 100% probability. The earthquakes of Mw~4.1–5.3 reach 100% in 10 years. Similarly, Mw~5.4–5.7 reaches to 100% in 20 years. Likewise, Mw~5.8–5.9, 6.0–6.1 and 6.2 reach ~100% in 30, 40 and 50 years, respectively. For large earthquakes of Mw~7.0–8.0, the probability of occurrence reaches >80% in 100 years. This observation strongly indicates that the likelihood of earthquakes occurring in the north-eastern region of India and its surrounding areas tends to increase over time. Further, the region was divided into four zones, namely Block I (26.5–28.5ºN; 89–95ºE), Block II (26.5–28.5ºN; 95–97.5ºE), Block III (23–26.5ºN; 93–97.5ºE) and Block IV (23–26.5ºN; 89–93ºE) based on seismicity and the major tectonic domains of the region. In terms of return period based on GR-relation and stochastic observations, we may conclude that the risk associated with occurrence of earthquake is highest in Block IV, followed by Block III, Block I and Block II respectively. Further, a comparison of the probabilities of earthquake return period considering seismogenic depths along with hypocentral depth data for different blocks was investigated for a comprehensive understanding of seismic occurrences over time. However, overall, the patterns and trends observed remain consistent, emphasizing the seismic activity within each block and its associated return periods. The stochastic observations and findings are elaborately accentuated in the article. [ABSTRACT FROM AUTHOR]

This paper presents a modified evaluation approach for the structural-capacity-reserve (SCR) based on the static stability behavior of single-layer spherical lattice shells to achieve more accurate assessment results of seismic damage endurance. The SCR index in this paper is calculated by integrating the redefined residual structural capacity (RSC) ratio based on post-earthquake static stability behavior within the range of damage degrees caused by strong earthquakes. Compared with the assessment work for seismic damage endurance in the existing literature, the proposed RSC ratio in this paper could take into account both ultimate load-bearing strength and residual deformation. Additionally, the specific quantitative indicator in the proposed assessment method should also be determined according to whether the residual nodal displacement of the lattice shell after an earthquake exceeds the limit value state specified by the design code. The numerical results in the case study indicate that the residual load-bearing strength of the lattice shell remains relatively constant under the same damage state induced by different earthquakes, with residual deformation significantly impacting the assessment of seismic damage endurance. Thereby, the required RSC can be controlled by reducing the residual nodal displacements of the lattice shell under strong earthquakes to achieve a well-balanced design scheme. [ABSTRACT FROM AUTHOR]

After the May 12 earthquake in Wenchuan, numerous debris flow disasters occurred due to heavy rainfall. After the earthquake, disaster prevention and mitigation projects, such as the sand dam, played an essential role in safety. However, when the outflow of solid material exceeds the designed storage capacity of the sand dam, the debris flow overtopping the dam intensifies the scraping effect on the source material of the gully channel. This paper takes the "8.20" debris flow in the Chutou gully as the research object. A transport mode of the debris flow after dam overtopping is studied through comprehensive field investigation, theoretical analysis, and indoor model tests. A quantitative evaluation model is established for the scraping depth and scraping volume of dam-overtopping debris flow. The study results showed that once the debris flow overtops a dam, the loose source carried by the channel is involved in the entire migration process, enlarging the fluid scale and intensifying the damage along the channel. The results agree with the measurements and observations, with maximum relative errors of 5.81% and 14.70%, respectively. This shows model validity. Furthermore, the test results show that the debris flow scarping phenomenon in the γ=[1.4 t/m3, 1.6 t/m3] interval is the most significant. Overall, this study will help improve future engineering decisions, design strategies, and finding the best design solutions to minimize the risk of dam-overtopping debris flow disasters. [ABSTRACT FROM AUTHOR]

In the present study, centrifuge tests for small-scale specimens were performed to investigate the dynamic soil pressure of the basement of buildings subjected to seismic ground motions. To investigate the effect of the embedded depth of basement, a deep basement model fixed to rock (model 1) and a shallow basement model embedded in soil (model 2) were tested. The soil pressures acting at the front wall (Dynamic soil pressure, DSP) and back wall (Soil pressure at back wall, BSP) were measured. Under the Northridge earthquake (with PGAb = 0.33 g), DSP of Model 1 (fixed based model) reached 100 kPa showing an increasing linear distribution from bottom to top. The DSP profile was similar to the profile of relative displacement between the basement and soil. Interestingly, BSP decreased to 0 as a gap occurred between the soil and basement wall. On the other hand, in the case of model 2 with a smaller depth, the relative displacement between the basement and soil was smaller due to the influence of flexible base. As a result, DSP (<20 kPa) was smaller and BSP was greater than those of the deep basement model fixed to rock. The tested soil pressures were compared with the predictions of existing models. [ABSTRACT FROM AUTHOR]

Recent geodetic and seismological observations of two major earthquakes in southeastern Türkiye in February 2023 have revealed complex rupture initiation, propagation, and segmentation along the East Anatolian Fault Zone (EAFZ) and surrounding regions. However, the role of upper crust structures along the EAFZ in determining the diverse rupture processes of this earthquake doublet remains unclear. To further investigate this, we employed double-difference location and seismic tomography techniques to determine high-resolution seismic velocities (VP, VS) and Poisson's ratio (σ) structures using a multi-parameter joint tomographic algorithm. Our dataset includes 100,833 high-quality source-receiver travel-time pairs of P- and S-waves. We find that the unique rupture processes of this earthquake doublet were primarily influenced by contrasting crustal seismic structures and localized geological settings. The Mw7.8 mainshock was initiated within a transitional edge zone characterized by a rigid part (asperity) of the seismogenic zone with sharp contrast variations in rock strength ranging from low to high along the EAFZ. In comparison, the Mw7.6 rupture originated in a ductile belt featuring fluid saturation with low-VP, low-VS, and high-σ values that extended parallel to the Çardak Fault. The pronounced contrast structures observed along the former rupture can be attributed to the oblique collision system between the weakened section of the east Anatolian plateau and the brittle Arabian platform, while the latter rupture was initiated within the ductile structure associated with fluid intrusion caused by the northward subduction of the Cyprus slab and subsequent detachment. Furthermore, the occurrence of the first earthquake (E1) serves to alleviate shear stress on the second earthquake (E2) fault, potentially impeding the initiation of an E2 rupture. On the contrary, this event also significantly reduces the normal stress acting on the E2 fault due to a double left-lateral strike-slip system within a triangular region. This reduction not only results in a decrease of fault friction force and an increase in rock porosity but also induces lower strain drops and the redistribution of Coulomb stress, thereby contributing to the initiation of the E2 event. The proposed rupture pattern exceeds the conventional model that governs individual earthquake ruptures, offering new insights for mitigating potential seismic disasters in Türkiye. The lessons learned from this doublet event can contribute to reevaluating the ongoing risk of damaging earthquakes in China's South-North Seismic Zone or other regions worldwide with comparable geological conditions. [ABSTRACT FROM AUTHOR]

This research innovatively presents a multi-parameter seismic fragility analysis methodology anchored on Blending ensemble learning tailored for the high-speed railway track-bridge (HSRTB) system. Leveraging ensemble machine learning models, a seismic demand model encapsulating multiple earthquake intensity measures (IMs) is formulated. The research progresses to deduce the mean seismic fragility representations for single, dual, and composite earthquake parameters. Key findings of this investigation underscore that the advanced methodology aligns well with the Monte Carlo (MC) fragility, signifying its robustness. Crucially, earthquake IM parameters, Sa(0.5) and Sa(0.3)_ASI, emerged as the optimal choices for singular and dual-parameter seismic fragility delineations. Further enriching this research, a composite parameter optimization technique rooted in multi-CPU genetic algorithms is proposed. This avant-garde method remarkably minimizes the fragility estimation error, emphasizing its unparalleled efficacy in enhancing the precision of fragility evaluations. [ABSTRACT FROM AUTHOR]

The present paper develops a new procedure for finding the most unfavorable long-period excitation for isolated building structures based on the probabilistic critical excitation method. The upper bound of earthquake input energy per unit mass is considered the problem's constraint, and a modified power spectral density (PSD) function is proposed to conform to the new constraint. It is shown that the new constraint can be used as a criterion to estimate the possible range of input energy of similar earthquakes. In addition, the new PSD function can control the excitation's intensity. Finally, three base-isolated shear buildings modeled as multi degree of freedom systems with nonproportional damping are considered, and the critical excitations for each model are found based on the proposed method. To examine the reliability of the results, three actual accelerograms with a considerably high level of total input energy are selected as benchmarks and linear dynamic analyses are conducted using these accelerograms along with the generated critical excitations. The results show that the generated long-period excitations can better estimate the structural behavior (i.e., maximum displacement, drift, and absolute acceleration of stories) than the actual benchmark accelerograms. [ABSTRACT FROM AUTHOR]

Seismic design tools are based on surrogate models of the designed structure and the responses of those surrogates to earthquake ground motions. To design symmetric flexible rocking structures, a surrogate model that includes rocking and flexure is needed. In this paper, we derive the equation of motion of a flexible multi‐degree‐of‐freedom (MDOF) structure rocking on its base in modal coordinates. Then, we introduce a set of two‐degree‐of‐freedom (2DOF) surrogate models that accounts only for the first elastic vibration mode of the multimass structure and its rotation about the base pivot points. We investigate the surrogates' ability to represent the dynamics of an elastic MDOF structure that uplifts and rocks and the interaction between rocking and flexure. Therein, we detail the simplifications for the equations of motion of the 2DOF surrogate models and the adopted rocking impact model, and develop and check the sliding initiation condition. We show that the simplified 2DOF surrogate model responses compare well to experimental results. Then we assess the 2DOF surrogate model accuracy in representing the earthquake response of the MDOF model using Cloud Analysis and the coefficient of determination R2$R^2$ approach. We find that simplified 2DOF surrogate of the MDOF model is quite accurate (R2=0.99$R^2\,=\,0.99$) in estimating its maximum relative top displacement and acceptably accurate (R2=0.90$R^2\,=\,0.90$) in estimating its maximum base rotation based on a thousand randomly generated flexible rocking structure earthquake response analyses. Lastly, we discuss using the simplified 2DOF surrogate model of symmetric flexible rocking structures in preliminary seismic design, and give examples featuring a continuous elastic hollow semi‐conical chimney and an inelastic flexible MDOF structure, both with a base that may uplift. [ABSTRACT FROM AUTHOR]

The assessment of human losses and injuries due to earthquakes is critical for the development of risk reduction measures. Yet, most vulnerability studies have focused on the derivation of fragility functions for structural damage, neglecting the evaluation of the human impact. In this study, we implemented a fatality vulnerability assessment procedure based on advanced structural modelling, with an application to typical limestone and granite masonry buildings in Portugal. We performed nonlinear time‐history analysis on 3D numerical models whose characteristics were sampled from statistical models representing the geometric and mechanical properties of this type of construction. Engineering demand parameters, such as volume of loss and volume of survivable space, were estimated and converted into a fatality rate based on observations from past fatal earthquakes. We compared these vulnerability functions with other proposals from the literature in which conventional fragility functions are directly combined with collapse and fatality rates. Finally, the resulting vulnerability functions were tested for two earthquake scenarios for Portugal. The results from this study indicate that the conventional approach for fatality modelling tends to underestimate human losses for strong ground shaking due to the inability to account for catastrophic structural collapses. The fatality vulnerability functions developed in this work can be directly used in probabilistic seismic risk analysis or the assessment of earthquake scenarios. [ABSTRACT FROM AUTHOR]

The emergency medical response after a strong earthquake relies on a robust transportation–healthcare system and effective management. This article proposes a resilience assessment framework for the interdependent transportation–healthcare system (ITHS) integrating physical loss and organisational management during post-earthquake emergency response. Considering the earthquake-induced injured people, the seismic damage to transportation, and the quantification of the condition of the patients after being treated, a novel metric is proposed to evaluate the response effort during the first 72 h. Bi-objective optimisation is developed to solve the real-time dispatching and treating problems instead of overwhelming one single hospital. In addition, the separate impact of disrupted transportation and damaged healthcare on the interdependent system is calculated to measure the cascading effect. It is shown that proper resource allocation and practical management are crucial to guarantee the desired level of the response effort. [ABSTRACT FROM AUTHOR]

Recent excavations and survey at the Roman and late antique city of Aeclanum provide important insights into developments across the fourth and fifth centuries CE at this site. Located in the inland region of Hirpinia, on the border of Apulia et Calabria and Campania, Aeclanum was insulated from some of the disasters that plagued the coastal regions in this period. It was, however, struck by two natural disasters: an earthquake in the mid-fourth century and the eruption of Vesuvius in 472 CE. Despite these events, new work suggests that the city remained a vital urban center even into the sixth century. In light of this new evidence, this article explores what the built remains, ceramics, and epigraphy reveal about the changing cityscape, economy, and society of Aeclanum. It further situates this evidence within its regional context to demonstrate how urban living was upheld, even in the face of significant environmental, religious, and administrative change. Our focus is on how human agency—of different forms—is manifest in the material evidence, and how this manifestation varies across available datasets and the networks between them. The availability of different datasets makes it a unique case study in this region and allows us to explore aspects of urban life in greater detail than is possible for many nearby cities. By using a pluralistic approach to material output, these examples reveal that, among some communities, circumstances and events long considered to be catastrophic to urban success were not as absolute as once thought. [ABSTRACT FROM AUTHOR]

Summary: The automated identification of building characteristics for seismic vulnerability remains a challenge for governments due to the high number of buildings in cities. The diverse architectural styles of these buildings complicate the automated identification of building information (e.g., number of stories, structural system, and material type). Deep learning techniques lose accuracy as they generalize information, while the visual contents of a building exhibit a considerable range and diversity. This study leverages the pose detection technique to tackle such issues by focusing on a common construction style: reinforced concrete buildings representing columns, beams, or floors on the façade. With an aim to enable the assessment of seismic vulnerability, the technique developed herein is conceived for buildings with up to six stories that are more likely to be moment‐frame buildings. The AI‐enabled proposed framework starts with collecting building images and categorizing those containing this specific building type. A bounding box detector is then used to isolate building facades, for the subsequent identification of the structural frame with the High‐Resolution Network (HR‐Net). For demonstration, we illustrate this technique by identifying the structural frame on concrete buildings with a sample dataset developed based on buildings found in Mexico City in a pre‐earthquake event state. [ABSTRACT FROM AUTHOR]

Summary: This paper evaluates the seismic performance of the frame‐bent structure of a conventional island main building in a nuclear power plant (NPP) using the CAP1400 NPP project of Rongcheng Shidaowan in Shandong Province as a case study. A 12‐pin 3‐span prototype structural model of a steel reinforced concrete (SRC) frame‐bent main building is established in ABAQUS, and its seismic fragility is analyzed. The results show that under the conditions of an 8‐degree frequent earthquake and an 8‐degree fortification earthquake, the transcendental probability under the four limit states of the structural seismic fragility matrix with Sa as intensity measure (IM) is higher than that with peak ground acceleration (PGA) as IM. Moreover, under an 8‐degree rare earthquake, the structure has completely exceeded the normal service performance level and has reached the service performance level of temporary use and repair. The seismic damage index of the structure demonstrates that the structure's seismic damage does not exceed the medium damage state under a small earthquake. However, under the action of a moderate earthquake, the seismic damage of the structure ranges from moderate to serious damage. When subjected to large earthquakes, the seismic damage of the structure is basically in a state of serious damage. [ABSTRACT FROM AUTHOR]

Interpretation plays a central role in using scientific models to explain natural phenomena: Meaning must be bestowed upon a model in terms of what it is and what it represents to be used for model explanations. However, it remains unclear how capacious and complex interpretation in models can be, particularly when conducted by the same group of scientists in the context of one explanatory project. This paper sheds light upon this question by examining modelling and explanatory practices related to the Olami-Feder-Christensen model of earthquakes. This case study shows that various interpretations are intricately connected in the overall meaning of a model used for model explanations. This leads to a manifold picture of interpretation, according to which scientific models are construed as networks of interconnected meanings. As scientists ponder and integrate these various interpretations, guided by locally attended epistemic interests, they achieve model explanations with layers of content, both in their explanantia and explananda. [ABSTRACT FROM AUTHOR]

SUMMARY: Large-scale and high-resolution seismic modelling are very significant to simulating seismic waves, evaluating earthquake hazards and advancing exploration seismology. However, achieving high-resolution seismic modelling requires substantial computing and storage resources, resulting in a considerable computational cost. To enhance computational efficiency and performance, recent heterogeneous computing platforms, such as Nvidia Graphics Processing Units (GPUs), natively support half-precision floating-point numbers (FP16). FP16 operations can provide faster calculation speed, lower storage requirements and greater performance enhancement over single-precision floating-point numbers (FP32), thus providing significant benefits for seismic modelling. Nevertheless, the inherent limitation of fewer 16-bit representations in FP16 may lead to severe numerical overflow, underflow and floating-point errors during computation. In this study, to ensure stable wave equation solutions and minimize the floating-point errors, we use a scaling strategy to adjust the computation of FP16 arithmetic operations. For optimal GPU floating-point performance, we implement a 2-way single instruction multiple data (SIMD) within the floating-point units (FPUs) of CUDA cores. Moreover, we implement an earthquake simulation solver for FP16 operations based on curvilinear grid finite-difference method (CGFDM) and perform several earthquake simulations. Comparing the results of wavefield data with the standard CGFDM using FP32, the errors introduced by FP16 are minimal, demonstrating excellent consistency with the FP32 results. Performance analysis indicates that FP16 seismic modelling exhibits a remarkable improvement in computational efficiency, achieving a speedup of approximately 1.75 and reducing memory usage by half compared to the FP32 version. [ABSTRACT FROM AUTHOR]

SUMMARY: On 6 February 2023, the Mw 7.8 Kahramanmaraş, Türkiye, earthquake occurred on the East Anatolian Fault Zone (EAFZ). This study examined the spatial variation of the stress field in and around Türkiye, particularly along the EAFZ, better to understand the rupture process of this event. We first combined focal mechanisms around Türkiye, created a data set consisting of 2984 focal mechanisms, and conducted stress tensor inversion. The results showed that the maximum compressional axis near the EAFZ was oriented north–south and slightly varied along the strike. Moreover, the relative magnitude of north–south compressional stress gradually increased from south to north, and the stress regime changes from a normal fault regime to a strike-slip fault regime. The static stress change caused by the 2023 Mw 7.8 and 7.7 events does not explain this lateral pattern, implying that this stress regime transition existed before the main shock. This suggests that shear stress on the EAFZ was low in this southern segment because it was unfavourably oriented to the regional stress field. Dynamic stress changes due to rupture propagation and dynamic weakening may have triggered the slip at the southern segment under low background shear stress. Previous studies have reported that the Mw 7.8 main shock rupture started at a splay fault, first propagated through the central and northern segments and then backpropagated with a time delay towards the southern segment, where it caused a significant but relatively small slip. The pre-existing along-strike shear stress variation on the fault may have contributed to the smaller and delayed coseismic slip in the southern segment than in the central and northern segments. The main shock rupture possibly caused stress rotation locally near the central segment where the magnitudes of the vertical and north–south compressional stresses were almost equal. [ABSTRACT FROM AUTHOR]

SUMMARY: Mode conversion of P waves at the boundary between Earth's crust and upper mantle, when analysed using receiver functions (RFs), allows characterization of Earth structure where seismic station density is high and earthquake sources are favourably distributed. We applied two ensemble decision tree algorithms—Random Forest (RanFor) and eXtreme Gradient Boost (XGBoost)—to synthetic and real RF data to assess these machine learning techniques' potential for crustal imaging when available data are sparse. The synthetic RFs, entailing both sharp increases in seismic velocity across the Moho and gradational Moho structures, calculated with and without added random noise, correspond to idealized crustal structures: a dipping Moho, Moho offset by crustal-scale faults, anti- and synform Moho structures and combinations of these. The RanFor/XGBoost algorithm recovers input structures well regardless of event-station distributions. Useful crustal and upper mantle seismic velocities can also be determined using RanFor and XGBoost, making it possible to image crustal thickness and P- and S-wave velocities simultaneously from RFs alone. We applied the trained RanFor/XGBoost to RFs determined from real seismic data recorded in the contiguous United States, producing a map of the Moho and P- and S-wave velocities of the lowermost crust and uppermost mantle. Use of XGBoost, which evaluates residuals between input RFs and ground-truth to update the decision tree using the gradient of a penalty function, improves the crustal thickness estimates. [ABSTRACT FROM AUTHOR]

SUMMARY: The mechanism responsible for the lateral expansion and uplift of the eastern Tibetan Plateau remains a topic of ongoing debate, partly due to discrepancies in the results of seismic velocity and anisotropy. In local earthquake tomography, hypocentral uncertainties can cause significant errors in the tomographic model. However, this issue has received limited attention in previous studies. In this work, we employ the weighted least-squares (WLS) method to solve the tomographic inversion problem. A power exponent coefficient, which is called weighting level, is introduced into the weighting matrix to control the relative contribution of the data with different hypocentral errors to the final tomographic result. Our data set contains high-quality Pg, Pn and Sg arrival times of local earthquakes recorded by the dense Chinese seismic network in eastern Tibet during 2008–2022. We comprehensively analyse the inversion results derived from the WLS inversions with different weighting levels to evaluate the robustness of isotropic velocity anomalies and azimuthal anisotropy. The most robust feature of our results is a striking low-velocity (low-Vp) zone surrounded by high-velocity (high-Vp) anomalies and fault parallel fast-velocity directions (FVDs) of azimuthal anisotropy in the lower crust beneath the western side of the Longmenshan fault zone. Taking into account many previous results of the region, we deem that the low-Vp zone reflects hot and wet upwelling flow from the deep asthenosphere, which ascends to the lower crust along the fault zone. At the NE margin of the Tibetan Plateau, significant low-Vp anomalies exist in the lower crust and the FVDs are consistent with the motion direction of the Tibetan block revealed by GPS (Global Positioning System) observations. We think that lower crustal flow exists beneath NE Tibet, which controls the plateau expansion toward the northeast. A low-Vp anomaly appears at 30 km depth beneath the Sichuan Basin. However, as the weighting level increases, the amplitude of this low-Vp anomaly decreases by more than 6 per cent, suggesting that this low-Vp anomaly has a lower accuracy than the other features. [ABSTRACT FROM AUTHOR]

This study explores the effects of social capital on the decisions of individuals in Turkey who experienced the earthquakes of February 6, 2023, to stay in the disaster area or move to another place during the recovery period. Qualitative research was conducted using an in-depth interview technique with 70 participants. The findings show that all three types of social capital (bonding, bridging, and linking) played a significant role in the recovery process for earthquake victims, but bonding social capital was particularly important in their relocation decisions. Additionally, this study reveals that bonding social capital acted as a buffer immediately after the earthquakes and effectively solved problems in the short term, but it was replaced by bridging and linking social capital in the medium term. Finally, negative impacts of social capital are shown to have occurred not only among immigrants but also among local people. [ABSTRACT FROM AUTHOR]

This study focuses on developing a relation between fundamental frequency (fo) and the depth of sediments above the bedrock. The fundamental frequency of the site ranges from 1.25 to 27.19 Hz, whereas the depth of sediments above the bedrock varies from 2 to 145 m. The eastern Shimla region has a fundamental frequency variation from 3.6 to 5.5 Hz, whereas the western and central parts have a fundamental frequency variation from 1.24 to 5.5 Hz and high frequency (>20 Hz) at isolated locations. The seismic data has also been recorded in active mode using MSOR (multichannel simulation with one receiver) to derive the dispersion curve, enabling the derivation of a 1-D, shear wave velocity (Vs) model using a joint fit modelling procedure. The 1-D profile shows variation in Vs from 180 m/s at the top to 760 m/s at bedrock. As per the National Earthquake Hazards Reduction Program (NEHRP) classification, the sites show that almost 40% of the city area fall under stiff soil and 60% fall under very stiff soil categories. Since most of the study region is covered with forest and sloping terrain, an empirical relationship (H = 154.36fo–1.451; R2 = 0.91) has been established for assessing the thickness of unconsolidated sediments. Furthermore, the thickness of sediments is determined by forward modelling by keeping the constant velocity at bedrock (Vb) 800 m/s. Additionally, the spatial map for sediment thickness is generated using the interpolation approach in combination with the forward modelling and regression analysis techniques. The derived relationship will provide major input for the area sharing similar geographical variability, where long active seismic profiles are not possible. [ABSTRACT FROM AUTHOR]

Surajkund Formation of Central Narmada Basin exhibits fining upward sequences of pebbly conglomerate, coarse-fine grained sandstone, siltstone and association of seven lithofacies, namely massive pebbly conglomerate, coarse-medium grained sandstone with large scale tabular cross bedding, massive coarse grained sandstone, coarse to medium grained sandstone with horizontal parallel bedding, fine grained sandstone with parallel lamination, fine grained sandstone with ripple lamination and siltstone, indicates their deposition in mixed load meandering river. Granulometric studies of Surajkund sediments also support the fluvial depositional environment. Soft sediment deformation structures documented in the siltstones suggest sediment liquification due to earthquake shocks. Abundant development of nodular, bedded calcretes and rhizoliths within these sediments are indicative of semi-arid climate and related subaerial exposure. These sediments are prominently lithic arenites, and clay mineralogy as well as geochemistry indicate deposition in the proximity of source, short distance of transport and mixed provenance of a variety of pre-Quaternary rocks such as Precambrian metamorphic rocks and granites, Vindhyan and Gondwana Supergroups, Deccan Trap basalt and laterite. Evidences of fresh water phreatic as well as vadose zone diagenesis linked to the semi-arid climatic conditions, together with subaerial exposure of these sediments, are seen in thin sections, which are supported by δ13C (av. −5.67%) and δ18O (av. −3.88%) values of calcretes. These values also suggest calcretes formed due to pedogenic and shallow groundwater processes in warm climate with C4-dominated vegetation. OSL date of one sample from Surajkund Formation gave an Ionian Age of Pleistocene Epoch. [ABSTRACT FROM AUTHOR]

Cyclic resistance curves, derived through undrained element tests, are central to the study of liquefaction. Their use implies that water drainage is negligible during an earthquake. Nevertheless, a growing body of evidence suggests that this hypothesis is not realistic. In proximity to the interface of a liquefiable layer with an overlying lower permeability layer, upwards water flow can lead to localised, co-seismic pore volume increase. The aim of this paper is to quantify the effects of pore volume increase on cyclic resistance curves. Cyclic triaxial experiments are presented, performed under undrained conditions and under conditions of volumetric expansion. A constant inflow rate is chosen for the sake of simplicity. Results show that even small inflow rates have a detrimental effect on cyclic resistance. A simplified methodology is developed, which can estimate cyclic resistance under constant water inflow rates, by assuming a superposition of isotropic unloading and undrained cyclic shearing. The results presented add to increasing evidence on how current liquefaction susceptibility assessments might not be conservative for layered deposits. In addition, they highlight significant aspects of soil response under partially drained conditions. [ABSTRACT FROM AUTHOR]

The building industry requires the development of a ductile lateral force resisting system made of mass timber to help mass timber to continue to grow in popularity as the primary structural building material. The OpenSees framework was used to develop a numerical model of a single-story timber frame with a timber buckling-restrained brace, which was validated by the results of a previously completed series of quasistatic cyclic timber buckling-restrained brace (TBRB) component and subassembly tests. The experimental validation included a model developed for the hysteretic behavior of the TBRB and the rotational capacity of beam–column joints made with mass ply lam (MPL) panels, two slotted-in steel plates, and a number of steel dowels. The single-story model TBRB braced frame was then expanded to a numerical model of an eight-story mass timber buckling-restrained braced frame. The TBRB frame was analyzed with static pushover, quasistatic cyclic loads, and earthquake simulations. During the simulation of eleven design-level earthquake ground motions, the building experienced a peak interstory drift at of 2.54% at the first-floor level and a peak floor acceleration of 1.7g at the roof. The numerical model developed in this research of a timber buckling-restrained braced frame with TBRBs is novel and could be used to design timber buckling-restrained braced frames as a ductile lateral force resisting solution for mass timber buildings in seismic regions. [ABSTRACT FROM AUTHOR]

Functional recovery is a new, nonstandardized building design objective, intended to improve a building's capacity to maintain or rapidly restore basic intended functions after a natural hazard event. Current building seismic design standards, which target life-safety performance objectives, provide limited requirements to ensure buildings maintain, or rapidly recover, function after earthquakes. Therefore, the expected functional recovery performance that is provided by current building codes is unclear. To provide clear and systematic insights to inform the development of prescriptive and performance-based design standards, this study documents the functional recovery performance for a set of 60 reinforced concrete archetype buildings. The results indicate that the estimated functional recovery time for reinforced concrete buildings designed to life-safety standards may approach 1 year, on average, for design-level earthquakes. Additionally, while increased strength and stiffness requirements significantly reduce the likelihood of a building being marked as unsafe due to structural damage, additional design provisions for nonstructural components are required to ensure a high confidence of rapid recovery. The findings from this study clarify the expected post-earthquake recovery of modern reinforced concrete buildings and identify key trends in underlying damage and response mechanisms required to improve future building performance. [ABSTRACT FROM AUTHOR]

Backbone curves were generated from previous physical lab tests conducted on identical full-scale RC components utilizing different loading protocols (slab–beam–column and column specimens). These curves were subsequently compared with those prescribed in ASCE 41. It was observed that there was a substantial difference between the two, with ASCE 41 backbones (based on standard tests) showing significantly lower ductility capacity compared to backbones from tests using a loading pattern representative of earthquake demands, leading to a near-collapse condition. A four-story archetype RC building was analyzed to assess the influence of different backbones on its seismic response. The analysis revealed that using backbones representative of earthquake demands produced a median spectral capacity somewhere from 25% to 50% greater than that obtained using ASCE 41 upper bound backbones. Similarly, for drift capacities at incipient collapse, it was found that using backbones representative of earthquake demands resulted in a median capacity somewhere between 1.6 and 2.9 times that of using ASCE 41 upper bound backbones. These differences are significant, implying that ASCE 41 can be overly conservative by rejecting buildings that would otherwise be acceptable if ASCE 41 criteria were based on tests using protocols representative of earthquake demands. Examination of the time-history responses of the study building revealed that earthquake demands were predominantly characterized by relatively few large drift excursions having a one-direction bias. Standard protocols differ significantly from responses observed during actual earthquakes, as they feature numerous symmetrical fully reversed cycles of drifts with progressively increasing amplitudes that are much more demanding. This leads to overly conservative ASCE 41 criteria (too pessimistic). It is concluded that future component lab tests must include protocols representative of earthquake demands to achieve more accurate estimates of component behaviors. Use of such protocols will lead to more appropriate (less conservative) ASCE 41 building evaluations, aligning more consistently with the philosophy of performance-based earthquake engineering. [ABSTRACT FROM AUTHOR]

Conventional semiempirical predictive models for seismically induced slope displacement (D) are generally developed based on as-recorded orthogonal ground motion components. Considering orthogonal records reveals that the predicted D is associated with intensity measure (IM) of a specific ground motion time history. However, current practice generally utilizes average IM (e.g., median over all horizontal ground motion orientations) as input of displacement models, and this tends to underestimate D when earthquake shaking along the downslope sliding direction is stronger than the average shaking level at a site. In this study, more than 190 million coupled sliding-block analyses were conducted using 3,092 ground motion records rotated over all orientations. Generic models were subsequently developed by integrating two machine learning algorithms for predictions of the maximum displacement (D100) or median displacement (D50) over all orientations. These models exhibit excellent generalization capability, yielding considerably lower bias and uncertainty than conventional polynomial forms. The results indicate that the predicted D100 could be significantly larger than D50 and the conventional displacement index for orthogonal records, and the D100 direction is dependent on both ground motion characteristics and slope properties. The proposed models outperform the existing models regarding ground motion directionality representation and prediction uncertainty mitigation. The associated mathematical equations are presented, with executable files also included for engineering applications. [ABSTRACT FROM AUTHOR]

This is the second of a two-part New Zealand Journal of Geology and Geophysics Special Issue on understanding sedimentary systems in Aotearoa-New Zealand's Hikurangi Subduction Margin (HSM). This volume includes six research papers that explore sediment-tectonic interactions operating over a range of spatio-temporal scales. We take a distinctive perspective moving from the subduction deformation front in the Hikurangi Trough, upslope to the subduction wedge, and onshore to the Coastal Ranges. Temporally, papers span the onset of subduction in the Miocene, to disentangling provenance of turbidity currents triggered by the 2016 CE Kaikōura Earthquake. Collectively, the studies in the special issue reveal a complicated and continually evolving margin, where active tectonics and volcanism, coupled with vigorous climatic and oceanographic drivers, modulate erosion, transport, and depositional cycles of vast volumes of terrigenous sediment into ocean basins. Despite decades of significant research advances in our knowledge of the HSM, considerable scope remains for future work. A deeper understanding of fundamental tectonic-sediment interactions operating on active margins, along with the significant geohazards they pose remain outstanding research needs. Collectively, Volumes 1 and 2 highlight enduring interest in the HSM as a globally important natural laboratory for the study of subduction zone geoscience. [ABSTRACT FROM AUTHOR]

The 2016 Mw 7.8 Kaikōura Earthquake triggered simultaneous turbidity currents down ten submarine canyons along a 200 km stretch of the continental slope, east of New Zealand. Some discharged into the Hikurangi Channel which flows >1500 km northwards along the abyssal trench floor. To better understand provenance continuity in deep-sea sedimentary records, foraminiferal samples from the 2016 turbidites from 17 canyon and channel cores were used to investigate the source histories of these submarine gravity flows. Cluster analyses suggest the canyon provenances for most 2016 turbidite faunas should be determinable using a combination of the relative abundance of key benthic genera, planktic foraminiferal index (dissolution), absolute test abundance and planktic % of the foraminiferal faunas. Two ordinations (PCA, PCO) based on these parameters were used to infer provenance and flow history. One hundred kilometres down the Hikurangi Channel, faunas in the 2016 turbidite confirm a Kaikōura Canyon source. Further downstream, 200–500 km north of the confluence with Campbell, Cook and Opouawe canyons, faunas indicate that the 2016 turbidite in the northern Hikurangi Channel is a composite deposit, from an initial Opouawe-Cook canyon-sourced turbidity current over-ridden and partly mixed with, a Kaikōura Canyon-sourced flow that arrived sometime later. [ABSTRACT FROM AUTHOR]

Megathrusts at convergent plate boundaries generate the largest and some of the most hazardous earthquakes on Earth. However, their physical properties, including those influencing fault slip accumulation and release and earthquake‐related surface displacements, are still poorly constrained at critical depths. Here, we combine seismic imaging and geodetic modeling to investigate the structure and mechanical behavior of the Main Himalayan Thrust fault (MHT) in the center of the 2015 Mw 7.8 Gorkha rupture in Nepal. Our results from two independent observations consistently suggest the presence of a channel associated with the MHT with high compliance (shear modulus as low as ∼4 GPa) and strain anisotropy (stiffer in the vertical orientation than in the horizontal), likely arising from a weak subducting layer with north‐dipping foliation. Such mechanical heterogeneity significantly influences the quantification of short‐term fault kinematics and associated earthquake potential, with implications on across‐scale dynamics of plate boundaries in Himalaya and elsewhere. Plain Language Summary: The Main Himalayan Thrust fault marks the boundary where the Indian continent slides beneath the Eurasian plate, causing earthquakes like the 2015 magnitude 7.8 event in Nepal. Subsurface images constructed using seismic waves suggest a weak layer surrounding the fault. However, we show that the seismic signature of this layer changes depending on the direction in which the seismic waves travel through it. We compare this information on the subsurface structure to insights from static surface motions during the earthquake. We find that the fit to the motion is poor when we assume the subsurface rock around the fault has the same strength in both horizontal and vertical orientations. The fit improves when we assume the near‐fault rock is stronger under vertical compression than under horizontal compression. This assumption also helps explain the images constructed using seismic waves. We suggest that a strong oriented rock fabric develops in a channel around the plate boundary. The presence of this fabric may have influenced our estimates of fault slip before, during and after great earthquakes. Accurately describing this behavior is crucial for understanding the earthquake potential of plate boundary faults. Key Points: Seismic imaging suggests a Main Himalayan Thrust‐associated low‐velocity channel with north‐dipping anisotropic foliationModeling of InSAR and GNSS data together suggests a weak channel with anisotropic rigidity whose orientation matches seismic constraintsThe weak anisotropic plate boundary may be related to S‐C fabrics and influence the margin geodynamics on different time scales [ABSTRACT FROM AUTHOR]

The 2024 Mw 7.5 Noto Peninsula, Japan, earthquake was initiated within the source region of intense swarm activity. To reveal the mainshock early process, we relocated the earthquake hypocenters and found that many key phenomena, including the mainshock initiation, foreshocks, swarm earthquakes, and deep aseismic slip, occurred at parts of a previously unrecognized fault in intricate fault network. This fault is subparallel (several kilometers deeper) to a known active fault, and the mainshock initiation and foreshocks occurred at the front of a 2‐year westward swarm migration. The initiation location coincides with the destination of the upward migration of a deeper earthquake cluster via several smaller faults. Fluid supply, small earthquakes, and aseismic slip on the fault likely triggered the mainshock, leading to the first major rupture at the western region, propagating further to the west and east sides, resulting in an Mw7.5 event, exceeding 100 km in length. Plain Language Summary: In 2024, an earthquake of magnitude 7.5 happened on the Noto Peninsula, Japan. This earthquake started in an area where many small earthquakes occurred. To reveal how this large earthquake occurred, we precisely determined the hypocenters of the mainshock, foreshocks, aftershocks, and swarm earthquakes. We observed that the mainshock initiation, foreshocks, and some aftershocks occurred on the largest fault in the complex network. Aseismic slip also occurred near the deeper extension. This fault is not a previously known active fault, but small earthquakes migrated westward on it for over 2 years, and the mainshock rupture was initiated at the front. Directly below the mainshock initiation area, small earthquakes moved upward through several small faults. Aseismic slip propagation, fluid supply, and small earthquakes likely triggered the mainshock. The initiated mainshock rupture caused the first major slip in the western region, causing considerable uplift there and further propagating to the east and west. Despite the existence of many minor faults, many key phenomena have occurred on this previously unrecognized fault, which plays a vital role in stress release and tectonic processes in this crust. Key Points: The mainshock initiation, foreshocks, and deep aseismic slip occurred on a previously unknown fault deeper than a known active faultMany swarm earthquakes that appeared to have occurred on different faults actually occurred on different parts of the same faultMainshock rupture was initiated in a westward earthquake migration front where fluid was supplied from depth through several small faults [ABSTRACT FROM AUTHOR]

The interplay between seismic activity and fluid flow is essential during the evolution of hydrothermal systems. Although earthquakes can trigger transient fluid flow and phase changes in dilational jogs, the temporal scale and the geologic conditions that enhance such process are poorly quantified. Here, we use numerical simulations of deformation and fluid flow to constrain the conditions that maximize adiabatic boiling—referred to as flashing—and estimate the extent and duration of such process. We show that there is an optimal geometry for a dilational jog that maximizes co‐seismic flashing within the jog. Fluid flow simulations indicate that the duration, intensity, and propagation of the flashing front are limited and highly dependent on the magnitude of the co‐seismic slip and the initial pressure‐enthalpy conditions. Our results are valuable to better understand the implications of pressure fluctuations during the seismogenic cycle, as well the mineralization processes in the Earth's crust. Plain Language Summary: Earthquakes can strongly affect circulating fluids within the Earth's crust, mainly where faults bend or split into different fault segments and produce dilatant areas. In these areas, earthquakes play an important role in forming ore deposits, because the co‐seismic volume change can produce a pressure drop that drives boiling with gas exsolution and subsequent mineralization. This process, in which boiling is triggered by a pressure drop rather than a temperature rise, is called flash vapourization or flashing. Here, we used a computer code to unravel scenarios where optimal geometry and pressure‐temperature conditions maximize flash vapourization. Furthermore, we found that the duration and extension of the flashing event are limited and highly dependent on the magnitude of the triggering earthquake and the physico‐chemical conditions of the system. Such results are valuable for assessing the implications of pressure fluctuations during the seismogenic cycle and for better understanding mineralization processes in the Earth's crust. Key Points: We use numerical simulations to constrain the intensity and temporal scale of co‐seismic flash vapourization or flashing triggered by earthquakesWe found an optimal geometry of a dilational jog that maximizes co‐seismic flashing within the jogsUnder optimal conditions, the flashing front propagates up to 1 m away from the dilational jog and persists for almost 3 hr [ABSTRACT FROM AUTHOR]

Tectonic landforms and surficial lithologic age are essential data for producing quality late Quaternary fault maps and predicting coseismic fault rupture location before an earthquake. However, we lack a clear understanding of the relationship between tectonic landforms and shallow earthquake processes and how lithologic age relates to landform preservation. We assess how fault location error (rupture‐to‐fault separation distance) and coseismic displacement residual (difference between observed and predicted coseismic displacement) vary with tectonic landform and lithologic age for four historical earthquakes. Certain tectonic landforms identified before these earthquakes correlate with lower fault location errors and median displacements below model predictions. Faults cutting Holocene units exhibit the largest location errors, reflecting surface processes that erode or bury fault evidence. This study shows that tectonic landforms and lithologic age have a significant impact on fault location uncertainty and coseismic displacement, which should be considered in fault mapping and fault displacement assessment. Plain Language Summary: Accurate maps of tectonic faults are essential for a variety of purposes including assessing seismic hazard, studying faults, and planning land‐use. These fault maps typically rely on identifying features in the landscape formed by past earthquakes. Remote sensing data sets like imagery and elevation support this process. However, a major challenge in fault mapping is figuring out how to best interpret what the landforms indicate about faulting. In this study, we analyzed how confident we are about the location of faults mapped before four historical earthquakes. We found that faults indicated by prominent landforms better indicate where subsequent earthquake ruptures will occur relative to faults indicated by less noticeable landforms. We also show that fault mapping in Holocene units (representing the most recent geologic time‐period) with meter‐scale remote sensing data is particularly challenging. Our findings support making better informed fault maps based on a deeper understating of how clues in the landscape connect to faulting processes. Key Points: Fault trace mapping is informed by tectonic landforms and surficial geologyUncertainty in fault location and predicted coseismic displacements correlate with tectonic landform type and lithologic ageFaults indicated by prominent tectonic landforms have relatively low fault location error and accommodate high displacement [ABSTRACT FROM AUTHOR]

Deep low‐frequency earthquakes (DLFE) are observed beneath volcanoes worldwide but are limited to island arc volcanoes, hotspot volcanoes, and rift zones. Here we show DLFEs in the Tengchong Volcano Field, southeast Tibet, located ∼300 km from the Indo‐Burma volcanic arc, by analyzing a 12‐year continuous seismic data set. The earthquakes were at a depth of ∼12 km, near the sidewall of the magma body detected by the magnetotelluric survey. The features of isotropic focal mechanism, episodic occurrence, and possible non‐power‐law scaling, with no detectable geodetic deformation, as well as the petrological signatures of the Holocene eruption product, suggest that the earthquakes were likely associated with the weak intermittent magma flows near the magma body. This finding may demonstrate the existence of unsteady magmatic processes in the margin of the Indo‐Eurasia collision zone, which could indicate unneglectable volcanic hazards, underestimated geothermal resources, and mineralization processes in similar regions. Plain Language Summary: Magmatic systems in the subduction arc, rift zone, and hotspot region are often active when magma stalls in the crust, indicative of unsteady magma dynamics and potential hazards. Holocene eruptions, present‐day structure anomaly, and geochemical signatures exist in some intra‐continent volcanos far away from the well‐predicted regions by plate tectonics. However, the magmatic systems there are thought to be relatively inactive. In this report, we show the first evidence of deep low‐frequency earthquakes occurring in the continental land on the edge of the Tibet Plateau, without any of the arc, hotspot, and rift volcanism involved. The observations' systematic characterization indicates weak but unsteady fluid flow currently occurring in this region. This finding demonstrates an unexpected behavior of the magmatic system in the continental collision zone, which may be underpredicted by the classic theory of plate tectonics on volcanism. Key Points: We report the discovery of deep low‐frequency earthquakes in the margin of the Tibet PlateauDeep origin, isotropic mechanism, low occurrence, and non‐power‐law scaling of the earthquakes are likely related to an unsteady fluid flowSeismic, petrological, and geochemical observations suggest the existence of juvenile magma flow beneath the Tengchong Volcanic Field [ABSTRACT FROM AUTHOR]