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The 2008 Mw 7.9 Wenchuan and 2013 Mw 6.7 Lushan earthquakes ruptured the central and southern segments of the Longmenshan thrust belt on the eastern Tibetan Plateau, respectively. The ∼M 7 Tianquan earthquake in 1327 is also thought to have occurred on the southern segment with effects spatially overlapping those of the Lushan earthquake, but the deformation style and seismogenic mechanism of the segment remain poorly understood. Satellite image interpretation, field investigations, and trenching reveal that the Shuangshi-Dachuan fault (SDF) on the southern segment displaces landforms, dips southeast, and is dominated by thrust motion with a left-lateral strike-slip component. The latest and penultimate events along the fault occurred in 1085–1457 CE and 1215 BCE-104 CE, respectively. Some ancient landslides exits along the fault, and one of them formed close to 703 ± 17 yr BP. The ages of the latest event and of the landslide agree well with the occurrence of the Tianquan earthquake, indicating that the earthquake was most likely generated by the SDF. Magnetotelluric imaging and the aftershock belt of the Lushan earthquake show that the Longmen Shan forms a wedge-shaped high-resistivity body protruding eastward. The SDF corresponds well to the east-dipping upper electrical boundary of the wedge-shaped body and is interpreted as a shallow backthrust; the seismogenic fault of the Lushan earthquake corresponds to the west-dipping lower boundary and is interpreted as a blind thrust fault. The left-lateral slip component of the SDF may be a response to the lateral extension of the weak lower crust. • The Shuangshi-Dachuan fault is a shallow backthrust of the Longmenshan thrust belt. • The Shuangshi-Dachuan fault (SDF) hosted the 1327 Tianquan earthquake. • The 2013 Lushan earthquake occurred on a blind thrust fault located under the SDF. • The SDF and the blind thrust fault correspond to the electrical structure boundary. • The electrical structure boundary had a controlling effect on the earthquakes. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The Lenglongling fault in the NE Tibetan Plateau hosts fresh scarps along the entire ∼120 km length. • UAV-based data and satellite images reveal 192 left-laterally offset geomorphic markers along the Lenglongling fault. • A binned cumulative offset probability density distribution reveals at least four paleoearthquakes. Abstract The Lenglongling Fault (LLLF) is located in the western section of the "Tianzhu seismic gap" along the Qilian-Haiyuan fault zone in the NE Tibetan Plateau, between the 1920 M8.5 Haiyuan and the 1927 M8.0 Gulang earthquakes. There is little information about the paleoseismic history of the LLLF and understanding the faulting history of the LLLF is important for determining the seismic hazards of both the fault and the seismic gap. Using UAV-based photogrammetry, high-resolution satellite imagery, and field investigations, we mapped the surface trace of the fault in detail and measured 192 left-lateral offsets of geomorphic markers along the fault trace. A binned cumulative offset probability density (COPD) distribution was calculated to analyze single-event and multi-event cumulative offsets. As a result, we find that the LLLF has fresh scarps along the entire ∼120 km length, indicating that the most recent event might have ruptured the full-segment of the fault. The coseismic offset of the most recent event changes along the fault trace and has an asymmetrical bell-shaped distribution. The maximum offset was ∼7 m, located in the middle-eastern section of the fault, and the offset decreases progressively towards both ends. The minimum offset, located at the western end, was ∼3.0 m, and the average coseismic offset was ∼4.8 m. The cumulative offsets of the four most recent paleoearthquakes are multiples of the coseismic offset of the most recent event, and show similar slip distributions, indicating that the fault ruptures with a characteristic slip. The fault slip distribution, estimated recurrence interval, and estimated moment magnitude imply that the LLLF releases accumulated strain energy mainly by repeatedly producing Mw 7.5–7.8 earthquakes every 1000 ± 200 years. We also show that the binned COPD technique performs well to separate single-event and multi-event cumulative offsets. [ABSTRACT FROM AUTHOR]

The Lenglongling fault (LLLF) is located along the northeastern margin of the Tibetan Plateau and forms a part of the Tianzhu seismic gap along the Qilian‐Haiyuan fault zone. Little is known about the recurrence of large earthquakes along the LLLF nor the associated seismic hazards of the gap. Here the six most recent surface rupturing paleoearthquakes of the LLLF are revealed by measurement of offset landforms, trench excavations, and radiocarbon dating. They are labeled E1–E6 from youngest to oldest, and their timings are constrained to the following time ranges: 636–498 to present, 2951–1155, 4016–3609, 5325–4476, 7284–6690, and 8483–7989 years BP, respectively. The LLLF displays evidence of fresh, recent surface rupture, and the trench sections reveal that the fault ruptured to the ground surface during the most recent event. Based on this fresh surface rupture and historical earthquake records, the latest event E1 was most likely the 1927 M8.0 Gulang earthquake. In conjunction with previous studies, Gulang earthquake might be a complicated event characterized by the combined rupture of both strike‐slip and thrust faults. The average recurrence interval of the six paleoearthquakes is 1643 ± 568 years, and the coefficient of variation is 0.34, indicating that the LLLF follows a quasiperiodic recurrence model. Based on this new understanding of the last event, the LLLF may not be a part of the Tianzhu seismic gap. However, an earthquake of up to MW7.6 could still rupture the gap sections composed of the Jinqianghe, Maomaoshan, and Laohushan faults. Key Points: Six recent surface rupturing paleoearthquakes of the Lenglongling fault were revealed by trench excavationsThe most recent event of the Lenglongling fault was most likely the 1927 M8.0 Gulang earthquakeThe Lenglongling fault may follow a quasiperiodic recurrence model [ABSTRACT FROM AUTHOR]

Understanding of treeline ecotone ecophysiological adaptation to climate warming is still very limited. Furthermore, it is difficult to predict which plant species could dominate in the future. For this reason, a study was conducted in the treeline ecotone, East Tibetan Plateau to detcct the adaptation of the dwarf willow ( Salix eriostachya) to experimental warming. Compared to ambient conditions, the experimental warming advanced the bud break by 12 days, delayed the leaf abscission by 20 days, and prolonged the growing period by 28 days. It also increased photosynthesis (47%), number of leaves (333%), leaf area (310%), and carbon sequestration of the dwarf willow. Experimental warming did not affect carbon use efficiency, but decreased water use efficiency significantly. Experimental warming enhanced the clonal ramets of Salix eriostachya (+ 3.7 shrubs m). The frequent air temperature fluctuations had minor effect on Salix eriostachya. Based on these findings, we highlighted that Salix eriostachya could dominate in the community treeline ecotone of east Tibetan Plateau in the future climate warming scenario. [ABSTRACT FROM AUTHOR]

Aim To investigate the population history and demographics of Jerdon's pitviper, Protobothrops jerdonii, and elucidate how the unique physical conditions and heterogeneous mountain environments resulting from the uplift of the Tibetan Plateau shaped the genetic diversity and evolutionary history of the species. Location China and Vietnam. Methods We sequenced and analysed a total of 1752 base pairs from two mitochondrial genes, cytochrome b (cyt b) and NADH dehydrogenase subunit (ND4), for 81 specimens sampled from 27 localities across the species' range, and a total of 464 base pairs from two nuclear genes for 28 representative samples from all mitochondrial DNA lineages. Based on these data, we constructed the genealogical relationships and estimated the divergence times of the mitochondrial DNA clades. Results The mitochondrial DNA results revealed the existence of five distinct, strongly supported and geographically structured DNA lineages within populations of P. jerdonii that are paraphyletic with respect to Protobothrops xiangchengensis. Estimation of divergence dates suggested that P. jerdonii possibly evolved in the western Hengduan Mountains region c. 6.6 Ma in the late Miocene. Nuclear DNA data did not provide sufficient resolution to distinguish the mitochondrial DNA lineages. Main conclusions Based on the present-day distribution and intraspecific genealogy, the evolutionary history of P. jerdonii can be explained by a pattern of dispersal followed by vicariance. All lines of evidence suggest that historical biogeographical factors, particularly the north-south orientation of the higher mountains, as well as low-elevation areas in western China, had the greatest influence on the population structure, lineage formation and species distribution of this snake. However, highly heterogeneous habitats and glacial cycles appear to have affected patterns of intraspecific differentiation. While our mitochondrial data provide evidence for clear phylogeographical structure, our small sampling of nuclear genes does not, suggesting that nuclear markers may not have had sufficient time to coalesce to match patterns observed in the mitochondrial data. [ABSTRACT FROM AUTHOR]

The snakes of the genus Thermophis, including two species (Thermophis baileyi and Thermophis zhaoermii), which are found only on the Qinghai-Xizang Plateau, were studied to determine the phylogenetic position of the genus within the broad superfamily Colubroidea. In this study, T. baileyi from two different localities in Xizang and T. zhaoermii from western Sichuan formed a monophyletic group as determined using Bayesian and likelihood methods of phylogenetic inference. Based on the nucleotide sequence of the cyt b and c-mos genes, Thermophis appeared to be a member of the subfamily Xenodontinae, which prior to this finding had been confined to a New World distribution. The molecular data also indicate a large genetic distance between T. baileyi and T. zhaoermii, which strengthens the validity of the new species: T. zhaoermii. [ABSTRACT FROM AUTHOR]

The temporal slip behavior of a fault from displaced landforms when there are no chronological data remains poorly understood. The southern segment of the Xiaojiang fault zone (XJFZ) plays an important role in accommodating the lateral extrusion of the SE Tibetan plateau. However, there are few reports on the evolution of the offset landforms and slip behavior of the fault due to the dense vegetation in the region. Here, offset landforms along the Jianshui fault (JSF) in the southern segment of the XJFZ are systematically interpreted and measured using high-resolution satellite imagery, field investigations, and airborne lidar. The risers on the right banks of three stream channels feature similar left-lateral offset characteristics near the town of Dongshanzhai. The left-lateral offsets consist of multiple inflections produced by seismic events, and the offset of each event is similar. These inflections are distributed downstream in a stair-stepped manner. The newly formed inflections are located close to the fault, and the earlier formed ones are eroded by flowing water and migrate downstream. The difference between the amount of downstream erosion of two adjacent inflections varies. Assuming the stream's long-term erosion rate remains steady, the estimated time intervals between seismic events are different. Combined with the cumulative offset probability density calculation for 92 offsets, the JSF is considered to show a nonperiodic characteristic earthquake recurrence pattern. We also propose a multistage offset evolution model of the stream channel riser. This provides a new way to analyze the seismic recurrence pattern of the fault over a relative time scale. [ABSTRACT FROM AUTHOR]

Abstract: We conducted phylogenetic analyses to identify the closest related living relatives of the Xizang and Sichuan hot-spring snakes (T. baileyi and T. zhaoermii) endemic to the Tibetan Plateau, using mitochondrial DNA sequences (cyt b, ND4) from eight specimens, together with sequences from 95 additional caenophidian and five henophidian genera that were downloaded from GenBank. Phylogenetic trees were obtained using Bayesian Inference and Maximum likelihood methods. Results suggest that hot-spring snakes, which are adapted to high and cold environments, were clustered in the monophyletic Xenodontinae. Xenodontinae is one of the largest subfamilies of colubrid snakes, with about 90 genera and more than 500 species known, and are primarily tropical snakes previously thought to be restricted to the New World. Our data failed to provide any evidence that the New World xenodontines diverged from Thermophis and dispersed into the New World, also failed to suggest a colonization of Asia by New World xenodontines by dispersal from the New World. An alternative plausible scenario may be that Thermophis and the New World xenodontines evolved independently in Asia and America, respectively, after the divergence of their common ancestor. The divergence of the two species in Thermophis was caused by the barrier of the Hengduan Mountains, and the speciation had almost occurred when Tibetan Plateau attained present elevation. [Copyright &y& Elsevier]