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Within the European TURNkey project, a knowledge-based exposure-modelling framework was developed, enabling the consideration of different levels of investigation and data availability. In particular, the proposed framework recognizes various levels and origins of uncertainties, as well as the completeness of a building stock catalogue. Despite substantial efforts, the main question still needs to be answered: How reliable can the developed tools and instruments be if they are not tested and validated by actual events? The L'Aquila 2009 earthquake has been the subject of several analytical strategies to enrich earthquake engineering knowledge. In this study, the information provided by the Italian Observed Damage Database is analyzed, explicitly focusing on the seismic sequence of the L'Aquila 2009 earthquake within the delimited area of the city's historical center. A second dataset, where the European Macroseismic Scale (EMS-98) was used as a reference, is integrated into the study, and the results are compared. A methodology is implemented for a systematically evaluating the database based on the EMS-98. From the data analysis, a proposal is made to define a comparable EMS-98 building typology and to assign vulnerability classes considering optimistic, pessimistic and most likely criteria. The reliability of the sample is then explored using the knowledge-based exposure modelling framework established by the TURNkey Project. Accuracy is then evaluated through an empirical inspection of frontal (lateral) views available in Google Street View (2022). Images before and after the event are collected and compared with the available data. Intrinsic problems encountered during the process are then listed and discussed, particularly regarding the use of the database, the joint between the studied datasets, and the post-processing required to use the data for damage prognosis. This paper intends to demonstrate how reliable datasets for the building stock, including structural types and corresponding vulnerability classes, can be elaborated. Not least, exposure modelling has to transform the available data into a descriptive form that can be linked directly with the Fragility or Vulnerability Functions, expecting that these assignments are the best suited or representative ones. The data layers provided by the study enable the testing and training of exposure modelling techniques for the selected event and target region. [ABSTRACT FROM AUTHOR]

Increasingly, post-earthquake cordons (PECs) have been used to support response and recovery activities around the world. However, thus far, the empirical analysis of cordons has not considered the overarching feasibility of their use. This research aims to fill this gap through a case study of Kathmandu Valley following the 2015 Gorkha earthquake in Nepal. It draws on a broader study that has investigated various aspects of cordons in New Zealand and Italy. In total, 13 interviews were conducted in the Nepali language with relevant experts of varying backgrounds and expertise such as academics, disaster management officers, policymakers, municipality representatives, and practitioners (INGO). The interviews were semi-structured and conducted through purposive and snowball sampling. The data was translated, transcribed, and then coded into NVivo software which was then analyzed inductively through an iterative thematic process. The findings of this research demonstrate the importance of context in understanding PECs and their implications on disaster response and recovery. For cordons to be feasible, many factors such as resource challenges (physical, economic, and human) and provisions for temporary housing, welfare, access to essential services, security, and availability of alternative transportation routes are essential. In addition, legislative frameworks, trust in government institutions, and cultural nuances need to be taken into consideration if PECs are to be feasible as a disaster response and recovery strategy. [ABSTRACT FROM AUTHOR]

Understanding under which physical conditions large earthquakes begin, is a key question in Earth science. Laboratory experiments and numerical models have shown that earthquake nucleation has distinct phases: a quasi‐static and an acceleration stage, followed by dynamic propagation. However, obtaining observations of such or similar processes in nature is complex. Here, we report on the rupture initiation of the Mw 6.1 2009 L'Aquila earthquake. From the detailed analysis of seismic waves recorded at several stations, we identify an ∼0.6‐s signal preceding the large dynamic rupture. From the geometrical characterization and rupture parameters of this initial phase, we infer that the rupture struggled to initiate exhibiting a slow rupture velocity (Vr=0.9±0.2 $Vr=0.9\pm 0.2$ km/s) and low seismic efficiency (η=0.24 $\eta =0.24$) due to a complex environment in the region where the rupture starts. We also show that the parameters of the rupture initiation are representative of scale‐dependent quantities for slip‐dependent nucleation models. Plain Language Summary: Understanding the process leading to a large earthquake is a key question in Earth science with implications for earthquake prediction and risk assessment. Although results from laboratory experiments and numerical simulations show that earthquake nucleation is composed of several preliminary stages, these stages and the associated processes are very difficult to observe in natural earthquakes. In this work we study the Mw 6.1 2009 L'Aquila earthquake, and show that it started with a slow rupture, where most of the energy was used to propagate the rupture. Our results show that the rupture struggled to initiate, and it did it slowly probably due to the conditions in which it starts. In addition, our results show similarities with previous work done for earthquakes in different regions of the world and also using theoretical models. Key Points: The initiation of the L'Aquila earthquake is characterized by a small amplitude signal before the onset of large amplitude P‐wavesWe evidence a slow rupture velocity during the rupture initiation of the L'Aquila earthquakeLow seismic efficiency indicates that most of the energy budget was used to initiate the rupture (fracture energy ∼76%) [ABSTRACT FROM AUTHOR]

This article will focus a aspect wich concerns the way in which a traumatic and catastrophic effect, such as an earthquake, has triggered mechanisms of human circulation, between victims, rescuers and workers who change their residences to the point of remaining citizens of that territory, creating an osmotic diffusion of knowledge that feeds on both the knowledge and cultures of origin and those of reception.DOI: https://doi.org/10.20365/disegnarecon.28.2022.6

The post-earthquake seismic assessment of buildings is usually performed through numerical methods. Geometrical simplifications of the structure are often introduced. Moreover, the seismic input is evaluated following the indications of reference standards, although overestimated forces may be obtained compared with those that actually occurred. In this paper, through the case study of a single-nave church, the significant influence of the geometric modeling of the roof on the structural response and the importance of the correct definition of the seismic input in post-earthquake analyses are shown, even in the case of very simple structural organisms. A preliminary limit analysis and nonlinear static analyses, after the definition of new response spectra based on a subset of the recorded ground accelerations, have been performed. The decisive role played by the correct geometric modeling and the proposed response spectra in the simulation of the overall response and damage status is shown. Finally, the importance of the method in the design of retrofitting works is highlighted through the basic example of the numerical response of the structure reinforced with CFRP composite. [ABSTRACT FROM AUTHOR]

The Summer School dedicated to Digital Humanities (DH) for Art History, held between 27 June and 1 July 2022 at the Department of Excellence of the Department of Human Sciences (DSU Scienze Umane) of the University of L’Aquila, represented a singular opportunity for an in-depth snapshot of a discipline that, de facto, has only recently managed to carve out a defined space within academia. This, all the while for decades having been a fundamental component of many research institutes’ activities and at the same time acquiring a predominant role in the vast world of protection, enhancement and dissemination of cultural patrimony.

This paper, written for the Summer School at L’Aquila, gives a brief overview of the current status of the ongoing research project for the digital edition of the Monumenti storici artistici della città di Aquila e suoi contornicolle notizie de’ pittori scultori architetti ed altri artefici che vi fiorirono (L’Aquila, 1848) by Angelo Leosini (L’Aquila, 1818–1881), with particular attention to the task of text transcription and markup.

Post-earthquake cordons have been used after seismic events around the world. However, there is limited understanding of cordons and how contextual information such as geography, sociocultural characteristics, economy, and institutional and governance structures affects decisions and operational procedures, including aspects related to spatial and temporal attributes of cordon establishment. This research aims to fill the gap in cordon knowledge through a qualitative comparative case study of two cities: Christchurch, New Zealand (Mw 6.2 earthquake, February 2011) and L'Aquila, Italy (Mw 6.3 earthquake, 2009). Both cities suffered comprehensive damage to their city centers and had cordons established for extended periods of time. Data collection was done through purposive and snowball sampling whereby 23 key informants were interviewed in total. Research participants held expert knowledge in their roles and responsibilities, that is, council members, emergency managers, politicians, business/insurance representatives, academics, and police. Results illustrate that cordons were primarily established to ensure safety of people and to maintain security. The extent and duration of the cordons were affected by the recovery approaches taken in respective cities, that is, in Christchurch demolition was widely undertaken which supported recovery and allowed for faster removal of cordons. In contrast, authorities in L'Aquila placed high value on heritage buildings which led to recovery strategy based on preserving and restoring most of the buildings which extended the duration of cordon. Extended cordons have many similarities but evolve overtime. This evolution of cordons is affected by site-specific needs; thus, cordons should be understood and planned based on contextual realities. [ABSTRACT FROM AUTHOR]

Static stress transfer from major earthquakes is commonly invoked as the primary mechanism for triggering aftershocks, but evaluating this mechanism depends on aftershock rupture plane orientations and hypocenter locations, which are often subject to significant observational uncertainty. We evaluate static stress change for an unusually large data set comprising hundreds to thousands of aftershocks following the 1997 Umbria‐Marche, 2009 L'Aquila (Italy), and 2019 Ridgecrest (California) earthquake sequences. We compare failure stress resolved on aftershock focal mechanism planes and planes that are optimally oriented (OOPs) in the regional and earthquake perturbed stress field. Like previous studies, we find that failure stress resolved on OOPs overpredicts the percentage (>70%) of triggered aftershocks relative to that predicted from observed aftershock rupture planes (∼50%–65%) from focal mechanisms solutions, independent of how nodal plane ambiguity is resolved. Further, observed aftershock nodal planes appear statistically different from OOPs. Observed rupture planes, at least for larger magnitude events (M > 3), appear to align more closely with pre‐existing tectonic structures. The inferred observational uncertainty associated with nodal plane ambiguity, plane orientation, and, to second order, hypocentral location yields a broad range of aftershocks potentially triggered by static stress changes, ranging from slightly better than random chance to nearly any aftershock promoted, particularly those further than 5 km from the causative fault. Dynamic stresses, afterslip, pore fluids, and other sources of unresolved small‐scale heterogeneity in the post‐mainshock stress field may also contribute appreciably to aftershock occurrence closer to the mainshock. Plain Language Summary: Large earthquakes are followed by a decaying number of smaller earthquakes, called aftershocks, which are hypothesized to occur on subsidiary faults and fractures stressed by the mainshock. The percentage of aftershocks potentially triggered by this mechanism depends on the locations and orientations of the aftershock faults, and is susceptible to observational uncertainties in these parameters. We evaluate the percentage of aftershocks encouraged by stress changes for the 1997 Umbria‐Marche, 2009 L'Aquila (Italy), and 2019 Ridgecrest (California) earthquake sequences using large, published aftershock data sets. While only ∼50%–65% of aftershocks are nominally encouraged by mainshock stress changes, observational uncertainties are large enough that any aftershock could be explained by random chance, or could have been triggered. We also test the common assumption that aftershock faults are oriented to maximize failure in the applied stress field. Contrary to this assumption, we find that aftershocks tend occur on planes oriented more consistently with pre‐existing mapped faults. Accounting for aftershock fault plane uncertainties is critical when evaluating the percentage of potentially triggered aftershocks. Additional sources of uncertainty or other triggering mechanisms may be required to explain aftershock occurrence, especially in the immediate vicinity of the mainshock. Key Points: Aftershock uncertainties increase the range of statically triggered events from little better than the chance to nearly any event promotedOptimally oriented planes for Coulomb failure misrepresent aftershock planes, which may be better represented by considering mapped faultsStatic stress triggering near the mainshock remains uncertain from receiver plane uncertainties, and not only source uncertainties [ABSTRACT FROM AUTHOR]

We investigate the preparatory phase of the 2009, Mw 6.1 L'Aquila earthquake in central Italy by analyzing the temporal evolution and spatial distribution of the seismic moment, M0, to radiated energy, ES. Our approach focuses on monitoring the deviations of the scaling between M0 and ES with respect to a model calibrated for the background seismicity. The temporal evolution of these deviations, defined as Energy Index (EI), identifies the onset of the activation phase 1 week before the mainshock. We show that foreshocks are characterized by a progressive increase in slip per unit stress, in agreement with the diffusion of highly pressurized fluids before the L'Aquila earthquake proposed by previous studies. Our results suggest that the largest events occur where energy index (EI) is highest, in agreement with the existing link between energy index (EI) and the mean loading stress. Plain Language Summary: Understanding how the machine generating large earthquakes works is one of the fundamental challenging scientific questions. Pioneering studies have shown that large magnitude earthquakes are sometimes anticipated by foreshocks and slip instabilities. Until now, retrospective analyses of foreshocks during the preparatory phase of large earthquakes have focused mainly on their distribution in space, time and magnitude. In this study, we show that also the dynamic properties of the rupture process associated to foreshocks evolve both in time and space. Our results indicate that the temporal evolution of radiated energy and size of small magnitude earthquakes provide useful information to identify the begin of the final activation phase of the 2009 Mw 6.1 L'Aquila, Italy, earthquake, in agreement with seismicity rate information. Our study suggests that, for the investigated case, foreshocks had dynamic characteristics distinct from those of normal rate (background) seismicity. Thus, it can contribute with new evidence to the open debate whether foreshocks are different phenomena from background seismicity. Key Points: We observe foreshocks dynamic characteristics before the 2009, Mw 6.1 L'Aquila earthquake in central ItalyDeviations of radiated energy over seismic moment from a reference model highlight the preparatory phase of the main eventForeshocks are characterized by a progressive increase in slip per unit stress, in agreement with diffusion of highly pressurized fluids [ABSTRACT FROM AUTHOR]

How faulting processes lead to a large earthquake is a fundamental question in seismology. To better constrain this pre‐seismic stage, we create a dense seismic catalog via template matching to analyze the precursory phase of the Mw 6.1 L'Aquila earthquake that occurred in central Italy in 2009. We estimate several physical parameters in time, such as the coefficient of variation, the seismic moment release, the effective stress drop, and analyze spatio‐temporal patterns to study the evolution of the sequence and the earthquake interactions. We observe that the precursory phase experiences multiple accelerations of the seismicity rate that we divide into two main sequences with different signatures and features: the first part exhibits weak earthquake interactions, quasi‐continuous moment release, slow spatial migration patterns, and a lower effective stress drop, pointing to aseismic processes. The second sequence exhibits strong temporal clustering, fast seismicity expansion, and a larger effective stress drop typical of a stress transfer process. We interpret the differences in seismicity behaviors between the two sequences as distinct physical mechanisms that are controlled by different physical properties of the fault system. We conclude that the L'Aquila earthquake is preceded by a complex preparation, made up of different physical processes over different time scales on faults with different physical properties. Plain Language Summary: In this work, we study the seismicity before the Mw 6.1 2009 L'Aquila earthquake. We first catalog nearly 5000 events from the continuous seismic record. We then analyze the spatio‐temporal evolution of this sequence with several physical parameters. We observe that the sequence is divided into two main sequences. Our results indicate that several different physical mechanisms (e.g., aseismic deformation, stress transfer due to earthquake interactions) and potential heterogeneities in the fault system (e.g., the distance between seismic regions) controlled how the earthquake sequence played out. Our observations show a complex spatiotemporal evolution during the precursory phase and challenge classic fault models that explain earthquake initiation as a process along a homogenous planar fault. Key Points: We build a dense, high‐resolution catalog of foreshocks before the M6.1 L'Aquila earthquakeOur catalog captures a complex two‐stage evolution of precursory seismicityWe interpret that the precursory seismicity is driven by aseismic slip and stress interactions between earthquakes [ABSTRACT FROM AUTHOR]

Memorial days of disasters represent an opportunity to evaluate the progress of recovery. This article uses sentiment analysis (SA) to assess post-disaster recovery on the 10th anniversary of L'Aquila's earthquake using Twitter data. We have analyzed 4349 tweets from 4 to 10 April 2019 with the hashtag: #L'Aquila that we have obtained from a third-party vendor. The polarity is first defined using a supervised classification based on experts' rules on post-disaster reconstruction and Grammarly tones. Then, this polarity is compared with the outcome of an unsupervised classification based on the pre-trained SA machine learning algorithm developed by MonkeyLearn. We have found a significant negative assessment of the post-disaster recovery process in L'Aquila. About 33.1% of the tweets had a negative polarity, followed by 29.3% tweets with a neutral polarity, 28.7% with positive polarity, and 8.9% unrelated to the anniversary. Further analysis of the tweets confirms that after 10 years, the reconstruction is still ongoing and that criticism of the recovery reported in the literature is also found in the tweets. Based on our analysis, the critical day to collect most of the data is the anniversary's exact day. Tweets from citizens and/or news agencies, which are more likely to express the reality experienced, are therefore more useful in understanding recovery than tweets from government officials and/or governmental institutions. From the total 4349 tweets, we can state that 2488 (57%) were correctly classified by the pre-trained SA machine learning algorithm developed by MonkeyLearn, while 1861 (43%) were misclassified. It means an overall accuracy (ACC) of 57% and a misclassification rate of 43% by the algorithm. We argue that our results have the potential to serve as a benchmark that can be used to compare other post-disaster recovery processes using the same Twitter-based SA on their anniversaries. [ABSTRACT FROM AUTHOR]

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Copyright of Archeologia Postmedievale is the property of Edizioni all'Insegna del Giglio and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)