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The Longshou Shan, located in western China, plays a crucial role in connecting the Tarim Continent with the North China Craton. It provides valuable insights into the Cenozoic intracontinental deformation, the complex dynamics of Eurasian tectonics, and the relationship between the pre-Cenozoic Tethys and Central Asian orogenic systems. Consequently, comprehending the evolution of the Phanerozoic era in this region holds immense significance. Zircon (U-Th)/He (ZHe) dating was conducted on three granite samples (n = 18) collected from the Longshou Shan. The ZHe dates of these granite rocks range from 7.2 to 517.7 Ma, showing a negative correlation with eU values. Furthermore, a limestone sample from the Longshou Shan yielded ZHe (n = 4) ages of 172.0–277.1 Ma and AHe (n = 4) ages of 17–111.9 Ma. The area has undergone complex tectonic processes involving multiple phases of uplift and burial. Using both forward and inverse modeling methods, we aim to establish plausible thermal histories. Our models reveal: (1) Late Paleozoic unroofing; (2) Early Mesozoic cooling and Late Mesozoic regional stabilization; and (3) Cenozoic reheating and subsequent cooling. By investigating the intricate thermal history of the Longshou Shan through multi-method modeling, we compare different approaches and assess the capabilities of single ZHe dating for understanding a thermal history. This research contributes to unraveling the region's geological complexities and aids in evaluating various modeling methods. [ABSTRACT FROM AUTHOR]

Paleoseismic studies are critical for the assessment and prediction of large earthquakes (M ≥ 7). These studies involve excavating and analyzing evidence from surface–rupturing earthquakes. However, they often face limitations in spatiotemporal resolution. The Yuguang Graben, located in the northern Shanxi Grabens of North China, contains an abundance of Quaternary loess that can be utilized for extending paleoseismic records. Fine-grained deposits of loess contrast sharply with gravel deposits of the colluvial wedge, making the wedge shape apparent. To enhance our understanding of earthquake behavior in the Yuguang Graben, we excavated a trench on terrace T2 of the Songzhikou segment of the Yuguang Graben Fault (YGF). We used LiDAR to obtain a high–resolution orthophoto of the trench wall. Through OSL dating of colluvial wedges and loess, we identified at least four large paleoseismic events with a magnitude of M ≥ 7 that occurred along the YGF. These events took place at >77.6 ± 5.1, 63.9 ± 5.1, 51.0 ± 4.3, and 37.3 ± 0.3 kyr, respectively. Combined with previous paleoseismic studies, we identified seven paleoseismic events since the late Pleistocene. These findings reveal that earthquakes occurring on YGF follow a quasiperiodic pattern with an average recurrence interval of about 12 ± 3 kyr. The elapsed time of the most recent earthquake near the recurrence interval suggests an increased risk of a large earthquake along the YGF. We also analyzed earthquake clusters generated by neighboring faults in the active northeastern boundary of the Ordos block. Our analysis indicated that fault interactions can affect the recurrence interval of earthquakes along single faults, while regional seismic activity tends to concentrate in time during a seismically active period. These observations underscore the importance of expanding paleoseismic records and exploring regional seismic hazards to gain a more comprehensive understanding of earthquakes. • Colluvial wedges on normal fault reveal new paleoseismic events. • Establishment of the paleoseismic sequence of the Yuguang Graben Fault for 77,000 years. • Improve the understanding of fault behavior located at the boundary of the Ordos block. [ABSTRACT FROM AUTHOR]

• Xiongpo structure is a superimposed deep fault-bend fold and shallow structural wedge. • Xiongpo structure is accommodated a horizontal shortening rate of 0.2 mm/yr. • LMS front is partitioned low shortening rates (<0.5 mm/yr) on individual structures. Cenozoic crustal shortening across the Longmen Shan (LMS) fold-and-thrust belt records the eastward growth of the Tibetan Plateau. Although the structural geometries of individual structures in the region have been studied, the kinematics and rates of deformation across these structures remain unclear. In this study, we construct a geological cross section to derive the subsurface structural architecture of the Xiongpo structure in the LMS piedmont using one seismic reflection profile, and data from two boreholes. The structure displays a superimposed deep fault-bend fold and shallow structural wedge with three splay thrust faults. Using two-dimensional kinematic models, based on fault-bend folding algorithm, we reconstruct three episodes of upper crustal shortening, with 7.0 ± 0.3 km of total shortening. Combining with previously published low-temperature thermochronology data, we further estimate that the structure has experienced an average shortening rate of ∼ 0.2 mm/yr since 40–25 Ma. We infer that the structure acted as the deformation front of the LMS fold-and-thrust belt between 40 and 25 Ma and 15–10 Ma driven by the eastward growth of the Tibetan Plateau. Finally, we review the shortening rates of other five structures within the LMS piedmont, and find that these six structures (including the Xiongpo structure) individually have undergone an average shortening rate < 0.5 mm/yr on each fault, suggesting that strain is partitioned along several structures within the LMS fold-and-thrust belt. We also show that the southern LMS piedmont has absorbed more upper crustal shortening than the central LMS, ∼0.5–0.7 mm/yr, since ∼2.6 Ma. [ABSTRACT FROM AUTHOR]

Abstract: The May 12, 2008, Mw 7.9 Wenchuan earthquake was induced by failure of two of the major faults of the Longmen Shan thrust fault zone along the eastern margin of Tibet Plateau. Our study focused on trenches across the Yingxiu–Bichuan fault, the central fault in the Longmen Shan belt that has a coseismic surface break of more than 200km long. Trenching excavation across the 2008 earthquake rupture on three representative sites reveals the styles and amounts of the deformation and paleoseismicity along the Longmen Shan fault. Styles of coseismic deformation along the 2008 earthquake rupture at these three sites represent three models of deformation along a thrust fault. Two of the three trench exposures reveal one pre-2008 earthquake event, which is coincident with the pre-existing scarps. Based on the observation of exposed stratigraphy and structures in the trenches and the geomorphic expressions on ground surface, we interpret the 2008 earthquake as a characteristic earthquake along this fault. The interval of reoccurrence of large earthquake events on the Central Longmen Shan fault (the Yingxiu–Beichuan fault) can be inferred to be about 11,000years according to 14C and OSL dating. The amounts of the vertical displacement and shortening across the surface rupture during the 2008 earthquake are determined to be 1.0–2.8m and 0.15–1.32m, respectively. The shortening rate and uplift rate are then estimated to be 0.09–0.12mm/yr and 0.18–0.2mm/yr, respectively. It is indicated that the deformation is absorbed mainly not by shortening, but by uplift along the rupture during the 2008 earthquake. [Copyright &y& Elsevier]

The Langshan range-front fault (LRF) is an active Holocene normal fault that borders Langshan Mountain and the Hetao Basin, northwest of the Ordos Plateau, China. In this study, paleoseismic trenching was undertaken at three sites (North–South): Dongshen village (TC1), Qingshan (TC2), and Wulanhashao (TC3). The paleoevents ED1, ED2, ED3 from TC1 were constrained to 6.0 ± 1.3, 9.6 ± 2.0, and 19.7 ± 4.2 ka, respectively. The single paleoevent (EQ1) from TC2 was constrained to about 6.7 ± 0.1 ka, and the paleoevents EW1, EW2, and EW3 from TC3 were constrained to 2.3 ± 0.4, 6.0 ± 1.0, and before 7.0 ka, respectively. With reference to previous research, the Holocene earthquake sequence of the LRF can be established as 2.30–2.43 (E1), 3.06–4.41 (E2), 6.71–6.80 (E3), 7.60–9.81 (E4), and 19.70 ± 4.20 (E5) ka BP. Events E1, E3, and E4 might have been caused by events with magnitudes of Mw 7.6–7.8 that ruptured the entire LRF. Event E2 might have been smaller magnitude, about M7.0, and ruptured only a portion of the fault. The vertical slip rate of the LRF at the Qingshan site is inferred as 0.9 or 1.4–1.6 mm/year in the last 6.8 ka. The slip rate at Wulanhashao is considered to have been close to, but not <0.66 mm/year since 15 ka BP. We deem the LRF is an unsegmented active fault. Although the possibility of missing events in Late Pleistocene can not be dismissed, we argue the Holocene paleoearthquake history is complete, indicating an average recurrence interval of ~2500 years. [ABSTRACT FROM AUTHOR]

The kinematic characteristics of the Sanguankou-Niushoushan fault (SGK-NSSF) are of great significance to the understanding of the extension of the arc tectonic belt in the northeastern margin of the Tibet Plateau. Using field surveys and various data collection methods, including large-scale geological mapping, measurement of typical topographies, and dating of sedimentary strata, it was determined that the SGK-NSSF exhibits obvious dextral strike-slip characteristics and thus is not a sinistral strike-slip fault, as believed by previous researchers. The results of this study show that the geological boundaries for the Paleozoic, Mesozoic, and Cenozoic eras were all dextrally dislocated by the fault, with the faulted displacements being similar. The maximum strike-slip displacement of the fault, after elimination of topographic effects, was found to be 961±6 m. The Sanguankou fault at the northern section exhibits obvious characteristics of more recent activities, with a series of small gullies having undergone synchronized dextral writhing after traversing the fault. The average horizontal slip rate of the fault since the late Quaternary was determined to be approximately 0.35 mm/a. The pre-existing fold structures formed during the late Pliocene were dislocated by the fault and became ex situ, indicating that dextral strike-slip of the fault could not have occurred prior to the late Pliocene. The maximum displacements and average slip rates were used to estimate the onset time of the dextral strike-slip activities of the fault as being after 2.7 Ma. In this study, the understanding of previous researchers concerning the extension in the northeastern margin of the Tibet Plateau was combined with analyses of the successive relationships between fold deformations and fault activities. This led to the finding that the extension in the northeastern margin of the Tibet Plateau reached the vicinity of the SGK-NSSF during the late Pliocene (∼2.7 Ma), causing regional uplift and fold deformations of the strata there. During the early Quaternary, the northeastern compression of the Tibet Plateau and the counterclockwise rotation of the Ordos block collectively resulted in the dextral strike-slip activities of the SGK-NSSF. This then formed the foremost margin of the arc tectonic belt extension in the northeastern margin of the Tibet Plateau. [ABSTRACT FROM AUTHOR]

Paleomagnetic studies on the syncollisional magmatic eruptions provide a direct way to understand when and where the Paleo‐Tethys closed. We report a well‐dated paleomagnetic pole from the southern Lancangjiang volcanic belt in western Yunnan of China. Stable Characteristic Remanent Magnetizations (ChRMs) were isolated from 21 sites at high temperatures following step‐wise thermal demagnetization. The data pass fold, reversal, and conglomerate tests and are interpreted to be primary thermal remanent magnetizations. The new paleomagnetic pole (46.1°N/176.2°E, K=44.9, A95=4.8°, N=21) yields a paleolatitude of 26.0 ± 4.8°N at the reference site (23.0°N/100.4°E) in the southern Lancangjiang area. This direct paleo‐latitudinal constraint on the Paleo‐Tethys suture zone in western Yunnan indicates that the north branch of the Paleo‐Tethys Ocean closed no later than the Carnian Age of Late Triassic, and confirms a geographic linkage between the North Qiangtang and Indochina Blocks at least during the Early Permian to Late Triassic. Plain Language Summary: The Asian continent is formed by the amalgamation of continental blocks such as the Tarim, North China, South China, Indochina, and Qiangtang. However, questions remained to answer: When did the ocean between them close? How did they drift from the south hemisphere to the north? In this study, we present a paleomagnetic constraint on the Paleo‐Tethys suture zone to quantify when and where the Paleo‐Tethys Ocean closed. The Paleo‐Tethys Ocean closed no later than the early Late Triassic at ~26°N. The Indochina and North Qiangtang drifted together from the south hemisphere to the north during the Permian‐Triassic. Key Points: The southern Lancangjiang volcanic belt formed at a paleolatitude of ~26ºN during the Carnian Stage of the Late TriassicThe north branch of the Paleo‐Tethys closed no later than the Carnian Stage of the Late TriassicA Permo‐Triassic geographic linkage between Indochina and N‐Qiangtang is confirmed [ABSTRACT FROM AUTHOR]

Previous studies have proposed that the Eastern Tibetan Plateau underwent ∼E–W oblique crustal shortening, due to the eastward extrusion of the plateau since ∼5–2 Ma to present. However, the effects of the oblique thrusting on the three-dimensional (3D) fold morphology and kinematics in the front of the Longmen Shan fold-and-thrust belt are still poorly understood. We use 3D seismic data to produce five 3D geometric models and compare our results with structural models of the Yanjinggou anticline in the Longmen Shan fold-and-thrust belt, to investigate the effects of oblique thrusting on 3D fold evolution. The results show that regional oblique thrusting occurred within the LMS fold-and-thrust belt, resulting in rotation and a curved structural morphology, and suggest that this process may be applicable globally to both small- and regional-scale structures, as well as larger-scale orogenic belts in obliquely convergent settings. • The effects of oblique thrusting on 3D fold geometry and kinematics are investigated. • The Yanjinggou anticline developed as a trishear fault-propagation fold with 1.2 km shortening. • The Yanjinggou anticline was affected by oblique thrusting at an angle of 55°. Three-dimensional (3D) subsurface seismic data acquisition and modeling are rarely undertaken; consequently, the complex effects of oblique thrusting on the 3D morphology and kinematics of folds are still poorly understood. We use 3D seismic data to produce five 3D geometric models and compare our results with structural models of the Yanjinggou anticline in the Longmen Shan fold-and-thrust belt, to investigate the effects of oblique thrusting on 3D fold evolution. 3D geometric modeling results reveal that oblique thrusting may cause fold asymmetry, vertical axis rotation, and a curved fold axis. 3D seismic interpretations and structural modeling suggest that the Yanjinggou anticline developed as a trishear fault-propagation fold and experienced a maximum shortening amount of 1.2 ± 0.1 km. The 3D structural and geometric models are consistent with paleomagnetic results, suggesting that the anticline was affected by oblique thrusting at an angle of 55° above a listric thrust fault with three fault ramps (19°, 30°, and 40°), causing the fold to rotate and develop a curved morphology. The integrated method used in this study to investigate the effects of oblique thrusting on 3D fold morphology and kinematics can be applied to regional oblique thrusting in the Longmen Shan and other fold-and-thrust belts worldwide. [ABSTRACT FROM AUTHOR]

Abstract The left-lateral slip rate of the Tianjingshan fault (TJSF) has been debated for several decades. Here, we measured displacements of geomorphic landforms and dated landform ages at two sites along the TJSF, to determine a late Pleistocene to Holocene slip rate of ~1.1 ± 0.2 mm/yr. We also derived a slip rate of ~1.1 ± 0.5 mm/yr using modern GPS data. Finally, by correlating available offset measurements with trenching-derived paleoseismic data, we obtained an average Holocene slip rate of ~1.2 ± 0.1 mm/yr for the TJSF. These fault slip rates over different time scales are in good agreement and are well constrained to 1.1 ± 0.2 mm/yr. The kinematics of the TJSF suggest that the TJSF has played an important role in accommodating the tectonic deformation of the northeastern Tibetan Plateau. Highlights • The slip rates of the TJSF over different time scales are in good agreement and are well constrained to 1.1 ± 0.2 mm/yr; • The fault behavior of the TJSF is characterized by a lower left-lateral slip rate. • The TJSF accommodates complex deformation between the Tibetan Plateau, Alashan block, and Ordos block. [ABSTRACT FROM AUTHOR]

Studies have shown that the growth of the Qilian Shan, the northeastern margin of the Tibetan Plateau, started ~10 Ma ago. However, when and how it expanded northwards is still under debate. Here we focus on the rock uplift pattern of the Yumu Shan, an active fault-related fold in the Hexi Corridor north to the Qilian Shan. Normalized channel steepness achieved from the analysis of river longitudinal profiles shows a spatially variant rock uplift pattern, with higher rates in the middle part and lower rates towards the west and east tips. The compression of the mountain is typically accommodated by fault-fold related shortening and vertical thickening. Apatite fission track thermochronology reveals that the growth of the Yumu Shan started ~4 Ma ago, similar to the work on active tectonics. Combining the onset ages of the growth of the Qilian Shan (10 Ma), Laojunmiao anticline (3–4 Ma), Baiyanghe anticline (3–4 Ma), Wenshu Shan (4.5 Ma) and Heli Shan (2 Ma), we draw an conclusion that the NE margin of the Tibetan Plateau initiated growth in the mid-Miocene and expanded to the Hexi Corridor and to the south of the Alxa block in the early Pleistocene. [ABSTRACT FROM AUTHOR]

Continental thrust faulting earthquakes pose severe threats to megacities across the world. Recent events show the possible control of fault structures on strong ground motions. The seismogenic structure of the 2008 Wenchuan earthquake is associated with high-angle listric reverse fault zones. Its peak ground accelerations (PGAs) show a prominent feature of fault zone amplification: the values within the 30- to 40-km-wide fault zone block are significantly larger than those on both the hanging wall and the footwall. The PGA values attenuate asymmetrically: they decay much more rapidly in the footwall than in the hanging wall. The hanging wall effects can be seen on both the vertical and horizontal components of the PGAs, with the former significantly more prominent than the latter. All these characteristics can be adequately interpreted by upward extrusion of the high-angle listric reverse fault zone block. Through comparison with a low-angle planar thrust fault associated with the 1999 Chi-Chi earthquake, we conclude that different fault structures might have controlled different patterns of strong ground motion, which should be taken into account in seismic design and construction. [ABSTRACT FROM AUTHOR]

We present results from a detailed investigation of the horizontal displacement distribution, timing of paleoearthquakes and left-lateral slip rate on the western Tianjingshan fault. Measurements of 240 offset streams and ridges confirm that the fault is left-lateral and record evidence of repeated ∼3–4 m coseismic offsets along the 60–km–long fault. This suggests that ∼6 earthquakes may have occurred along the entire western Tianjingshan fault with repeated occurrence of earthquakes of Mw 7.2–7.5. Structural and stratigraphic relationships exposed in our five trenches in combination with previously reported studies further indicate that the fault has ruptured in as many as six paleoearthquakes since the late Quaternary. Paleoseismic data show that the average recurrence interval for Holocene earthquakes is approximately 5,000 yr. The most recent earthquake along the western Tianjingshan fault occurred ∼1.2 ± 0.1 kyr BP, indicating that this fault segment did not rupture in the M 7.5 historical earthquake of 1709 that ruptured the central Tianjingshan fault. We estimate that the Holocene slip rate of the western Tianjingshan fault is ∼1.1–1.2 mm/yr based on measurements of the age and offset of stream channels. Compared with the relatively fast slip rate of the Haiyuan fault (∼4–6 mm/yr), we suggest that the Tianjingshan fault acts as an essential active fault accommodating the sinistral displacement and crustal shortening deformation in NE Tibet. [ABSTRACT FROM AUTHOR]

We examined the regional scale topography of the Qilian Shan on the northeastern margin of the Tibetan plateau. Longitudinal profiles and geomorphometric indices, such as slope, local relief and channel steepness reveal that the Qilian Shan was developed as a local plateau with high-relief steep marginal ranges, and interior low-relief topography. Landscape mapping across this local plateau revealed spatially varied origins of the low-relief landscape in the Qilian Shan. North of the Haiyuan fault, universal massive intermontane aggradation was identified. However, the low-relief plateau to the south of the Haiyuan fault was dominated by relict erosional surfaces, even though accompany basin-filling still contributes. The geomorphologic contrasts led us to integrate both the basin-filling processes and antecedent low-relief erosional surfaces into a new insight into the development of the Qilian Shan plateau in the northeastern Tibet. Our present study highlights that explanation for the low-relief plateau formation needs to consider the complex geological evolution of the Qilian Shan, and the Tibetan Plateau itself. [ABSTRACT FROM AUTHOR]

The Longxian-Baoji Fault Zone (LBFZ) is the main structural link between the compressional Liupanshan Mountain in north and the extensional Weihe Basin in south, which accommodated complex deformation between the Tibetan Plateau and the Ordos Block. We determined the tectonic activity of the normal faults in the LBFZ using combined ridge and stream profiles measured from the natural landscape and simulated by a numerical model. The well-preserved geomorphic features (i.e., scarps) and steep scarp slopes show that the Guguan-Guozhen Fault (GGF) has been active during the Late Pleistocene to Holocene. The distinct decrease of scarp heights of the GGF near Badu and the low scarp and land surface slopes of ridge and stream profiles for the inferred northern extension of the GGF demonstrate that the GGF terminates near Badu and does not extend farther to the north. The Taoyuan-Guichuansi Fault is determined to be an Early-Middle Pleistocene fault, as evident from the different shapes and low scarp slopes of stream profiles. The longitudinal profiles of the Qianyang-Biaojiao Fault are characterized by two segments with different slopes, indicating that the fault may not have been active during the Quaternary. Our results show that the profile shapes, spatial pattern of scarp height, and the slopes of scarp and land surface of ridge and stream profiles are appropriate metrics of fault activity. Furthermore, we constructed the landform evolution in the LBFZ and suggest that it is closely related to the active tectonics. The change in fault activity reflects a tectonic transformation from an extensional regime to a dominantly transtensional regime. • Tectonic activity of the Longxian-Baoji Fault Zone analyzed from DEMs and modelling • Profiles and slopes of streams, interfluve ridges, fault scarps and land surfaces analyzed • Morphological differences suggest different activity and timing between different faults • Spatial-temporal fault pattern insights used to construct a landform evolution model • LBFZ topography linked to change in active tectonics from extension to transtension [ABSTRACT FROM AUTHOR]

On April 20, 2013, a Mw 6.6 earthquake struck Lushan County of Sichuan Province, China, about 80 km southwest of the epicenter of the 12 May 2008 Wenchuan Mw 7.9 event. It triggered a large number of landslides in a broad area, causing causality and injuries and damages to roads, drains, dwellings, and infrastructures. Field investigations of coseismic landslides provide a basis for better understanding and illustrating the spatial distributions and hazards related to the Lushan earthquake-triggered landslides. Therefore, this paper presents results of field investigations of the Lushan earthquake-triggered landslides, which can be classified into two main categories of disrupted landslides and coherent landslides, and constitutes seven types. The disrupted landslides include five types: rock falls, rock slides, rock avalanches, soil falls, and soil slides; and the coherent landslides have two types: soil slumps and slow earth flows. All of the seven types of landslides can be observed in many field photos, aerial photographs, and/or satellite images. Among them, seven typical large-scale landslides, distributed in a northeast trending line consistent with the Shuangshi-Dachuan fault, which is presumably related with the earthquake, are described in detail. We prepared an original, emergency-based coseismic landslide inventory map based on visual interpretation of available post-earthquake aerial photographs and pre-earthquake satellite images, combined with results from emergency-based field investigations. The original inventory map registered 3884 landslides. Later, 11,761 more landslides were identified by much more careful and time-consuming visual interpretation based on the same aerial photographs and satellite images. Subsequently, all the 15,645 coseismic landslides were correlated with six common landslide impact factors, including elevation, slope angle, slope aspect, topographic position, stratum/lithology, and peak ground accumulation (PGA). These observational and compiled coseismic landslide data allow us to make subsequent compiling of a detailed and completed landslide inventory by visual interpretation of remote sensing images as well as further studies of landslides induced by the Lushan earthquake. [ABSTRACT FROM AUTHOR]

On July 22, 2013, an earthquake of Ms. 6.6 occurred at the junction area of Minxian and Zhangxian counties, Gansu Province, China. This earthquake triggered many landslides of various types, dominated by small-scale soil falls, slides, and topples on loess scarps. There were also a few deep-seated landslides, large-scale soil avalanches, and fissure-developing slopes. In this paper, an inventory of landslides triggered by this event is prepared based on field investigations and visual interpretation of high-resolution satellite images. The spatial distribution of the landslides is then analyzed. The inventory indicates that at least 2330 landslides were triggered by the earthquake. A correlation statistics of the landslides with topographic, geologic, and earthquake factors is performed based on the GIS platform. The results show that the largest number of landslides and the highest landslide density are at 2400m-2600m of absolute elevation, and 200m-300m of relative elevation, respectively. The landslide density does not always increase with slope gradient as previously suggested. The slopes most prone to landslides are in S, SW, W, and NW directions. Concave slopes register higher landslide density and larger number of landslides than convex slopes. The largest number of landslides occurs on topographic position with middle slopes, whereas the highest landslide density corresponds to valleys and lower slopes. The underlying bedrocks consisting of conglomerate and sandstone of Lower Paleogene (Eb) register both the largest number and area of landslides and the highest landslide number and area density values. Correlations of landslide number and landslide density with perpendicular- and along-strike distance from the epicenter show an obvious spatial intensifying character of the co-seismic landslides. The spatial pattern of the co-seismic landslides is strongly controlled by a branch of the Lintan-Dangchang fault, which indicates the effect of seismogenic fault on co-seismic landslides. In addition, the area affected by landslides related to the earthquake is compared to the relationship of "area affected by landslides vs. earthquake magnitude" constructed based on earthquakes worldwide, and it is shown that the area affected by landslides triggered by the Minxian-Zhangxian earthquake is larger than that of almost all other events with similar magnitudes. [ABSTRACT FROM AUTHOR]

In the epicenter of the Lushan M7.0 earthquake there are several imbricate active reverse faults lying from northwest to southeast, namely the Gengda-Longdong, Yanjing-Wulong, Shuangshi-Dachuan and Dayi faults. Emergency field investigations have indicated that no apparent earthquake surface rupture zones were located along these active faults or their adjacent areas. Only brittle compressive ruptures in the cement-covered pavements can be seen in Shuangshi, Taiping, Longxing and Longmen Townships, and these ruptures show that a local crustal shortening occurred in the region during the earthquake. Combining spatial distribution of the relocated aftershocks and focal mechanism solutions, it is inferred that the Lushan earthquake is classified as a typical blind reverse-fault earthquake, and it is advised that the relevant departments should pay great attention to other historically un-ruptured segments along the Longmenshan thrust belt and throughout its adjacent areas. [ABSTRACT FROM AUTHOR]