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The northern segment of the Tanlu fault zone, which encompasses the Dunhua–Mishan and Yilan–Yitong fault zones, plays a critical role in the tectonic framework of Northeast China. This study focuses on the Hunhe fault, part of the Liaoning segment of the Dunhua–Mishan fault zone, which exhibits concealed characteristics and an NE–NEE orientation. We employ remote sensing and field investigations to accurately delineate the Hunhe fault's location, scale, and tectonic activity. The findings indicate that the Hunhe fault displays significant spatial variability in tectonic activity. Some segments show evidence of late Quaternary activity, contradicting prior research that classified the Hunhe fault as an active fault during the MIS (Marine Isotope Stages) 20-103MIS 20-103- MIS6-19MIS6-19 period and assessed its seismic potential differently. Recent field investigations suggest considerable spatial variability in tectonic activity, indicating segmental characteristics. In this study, the Hunhe fault is divided into segments based on five aspects: the fault structure and movement characteristics of the fault; transverse faults and obstruction structures; geological and geomorphological characteristics; seismic features; and fault activity. The detailed segments are as follows: the Shenyang segment, the Fushun segment, the Zhangdang-Nan Zamu segment, and the Nan Zamu to Ying Emeng East section. These findings aim to enhance the understanding of the seismic hazard potential associated with the Hunhe fault, highlighting the need for ongoing research to address its complexities and implications for regional seismic risk assessment. [ABSTRACT FROM AUTHOR]

Surface unloading due to impact cratering results in lava filling the crater floor. Elevation differences in the crater floor, a common geological phenomenon on the Moon, represent direct evidence of cratering processes. However, few studies have been conducted on mare-filled craters on the Moon. Al-Biruni (81 km) is a farside impact crater with an inclined topographic profile on its floor. We quantitatively measure the morphology of Al-Biruni and model the basaltic lava emplacement to depict the cratering process. Differential subsidence due to melt cooling, wall collapse, impact conditions and structural failure were assessed as potential factors influencing the formation of the elevation differences on the floor. The results suggest that pre-impact topography is a plausible cause of the differences in floor elevation within Al-Biruni. Other factors may also play a role in this process, affecting lava flow by altering the topography of the crater floor after the impact. Thus, regardless of whether the lava inside the crater is impact-generated or comes from outside the crater, altering topography at different stages of the cratering process is an essential factor in creating the sloped terrain on the crater floor. [ABSTRACT FROM AUTHOR]

According to historical records, an M 6¾ earthquake occurred in Nyemo, Tibet on April 21, 1901 without any reports on its seismogenic structure yet. To sort out its seismogenic structure helps to understand the earthquake recurrence pattern of the Nyemo graben group (NGG) and to scientifically evaluate the future earthquake risk of surrounding areas. According to our results from the remote sensing interpretation and geological survey, a 30 km-long fault with a trend of nearly NW-NNW at the western boundary of the Panggang graben (PG), one of the NGG, is divided into north segment and south segment by the Penggang River. The north segment is characterized by significant linear features, with fault scarps developed, offsetting multistage river terraces and moraines. The recovered displacements show that the vertical offsets of Terrace T0, T1 and T2 are ~1.0 m, ~2.6 m and ~5.0 m, respectively. The south segment with obvious linear features develops along the Xiaqing River and extends to the north Nyemo County, with fault scarps developed, offsetting multi-stage alluvial fans. We found the offset Terrance T2 profile in northern Nyemo, indicating the extension of the fault. Through the magnitude recovery, we calculated the moment magnitude of the latest earthquake as about MW6.8 along the PG, which is consistent with the Nyemo earthquake. Inferred from the results of the satellite image interpretation, geological survey and magnitude recovery, the PG is likely the seismogenic structure of the Nyemo earthquake. Also based on historical seismic records, we consider that each graben in the NGG could independently generate moderate-strong earthquakes, and the earthquake recurrence pattern and the seismicity difference between the NGG and the north and south segments of the Yadong-Gulu rift need further study.

The location of the main boundary fault of the Yadong-Gulu Rift (YGR) shifts from the east side in the southern segment to the west side in the northern segment. The Nyemo Graben Group (NGG) connects the southern and northern segments of the YGR and provides clues for understanding the migration of boundary fault locations along the YGR. However, the NGG has received very little attention. In this study, we map the geometry of the Pabu normal fault, which is the boundary fault of the westernmost graben in the NGG, using high-resolution remote sensing images. We then utilized a digital elevation model (DEM) with a spatial resolution of 1 m. Morphometric parameters such as scarp height, width, and slope were obtained from elevation profiles in three typical deformation regions. Our results reveal a fault segment approximately 3 km long that links the southern and northern segments of the Pabu Fault. Each fault segment could be a major segment. Furthermore, based on regional tectonic activity, the Pabu Fault has the potential to produce an earthquake with a magnitude of around M 6.7. [ABSTRACT FROM AUTHOR]

The tectonic deformation of the southeastern margin of the Tibetan Plateau underwent significant changes before and after the Miocene, which led to the change of the deformation characteristics of the Sichuan‐Yunnan block, and some local areas in the block also showed structural patterns inconsistent with the macroscopic clockwise rotation deformation. Moreover, the Chenghai fault (CF) in the Sichuan‐Yunnan block was the seismogenic fault of the M 73/4 Yongsheng earthquake in 1515. However, the dense vegetation impeded the acquisition of surface deformation characteristics and small‐scale horizontal offsets along the fault, resulting in its misty kinematic properties, roughly determined geometric distribution, and the highly controversial rupture parameters of the Yongsheng earthquake. Therefore, we used airborne light detection and ranging, which can penetrate vegetation to obtain high‐resolution surface topography, to map the CF within 120 km. Combined with satellite images and field investigations, we determined that the CF consists of a series of secondary faults with simple geometric structures. Continuous offset linear landforms were preserved along the fault. 102 offsets below 30 m were statistically analyzed and the result revealed that the CF has a characteristic displacement of ∼6 m and it may rupture as a united rupture segment in each large earthquake or its two rupture segments cascade rupture to generate large earthquakes. The magnitude of the Yongsheng earthquake in 1515 was estimated at 7.7. Finally, based on this study, the kinematic characteristics of the Dali terrane and Sichuan‐Yunnan block, where the CF is located are discussed. Key Points: We obtained the fine geometry of the Chenghai fault (CF) and determined its kinematic propertyWe reestimated the magnitude of the Yongsheng earthquake in 1515We discussed the seismogenic pattern of the CF and kinematic characteristics of the Dali terrane and Sichuan‐Yunnan block [ABSTRACT FROM AUTHOR]

Based on field investigations, interpretations of high‐resolution UAV images, and analyses of available InSAR data, we mapped the fault geometry and surface ruptures of the 2021 Mw 7.4 Maduo earthquake that occurred on a low‐activity strike‐slip fault within the Tibetan Plateau. The results indicate that (a) the earthquake activated a fault that is ∼161 km long and has complicated structural geometry; (b) the surface rupture occurs over a distance of 148 km, but is separated into three distinct segments by two large gaps (38 and 20 km, respectively); (c) within the surface‐rupture segments, the horizontal and vertical displacements are typically 0.2–2.6 m (much lower than the InSAR‐based slip maximum of 2–6 m at depth) and ≤0.4 m, respectively. The two large gaps of the Maduo surface rupture represent the two largest surface‐rupture discontinuities of strike‐slip earthquakes ever documented, and coincide with structurally complicated fault portions and near‐surface soft sediments. Plain Language Summary: Evaluating the seismic potential of low‐activity strike‐slip faults is commonly challenging because of (a) the difficulty in mapping of causative fault geometry that has subtle topographic expression, and (b) limited fault slip at the surface (relative to that at depth) produced by each earthquake. Our investigation of the 2021 Maduo earthquake demonstrates that, along the low‐activity strike‐slip fault, laterally significant gaps (up to 40 km wide) may separate extensive co‐seismically ruptured regions on either end of such gaps, which can thereby compromise typical methodologies used to assess paleoseismic ruptures and may lead to underestimates of seismic hazard. This observation increases the challenge of assessing the seismic potential of low‐activity strike‐slip faults. Key Points: The Maduo earthquake activated a 161‐km‐long strike‐slip fault with subtle topographic expression and complicated structural geometryThe surface rupture occurs over a distance of 148 km, but includes two large gaps that are 38 and 20 km, respectivelyWithin the surface‐rupture segments, the horizontal slip is 0.2–2.6 m, much lower than the InSAR‐based slip maximum of 2–6 m [ABSTRACT FROM AUTHOR]

The north trending rifts in southern Tibet represent the E–W extension of the plateau and confirming the initial rifting age is key to the study of mechanics of these rifts. Pagri–Duoqing Co graben is located at southern end of Yadong–Gulu rift, where the late Cenozoic sediments is predominately composed of fluvio‐lacustrine and moraine. Based on the sedimentary composition and structures, the fluvio‐lacustrine could be divided into three facies, namely, lacustrine, lacustrine fan delta and alluvial fan. The presence of paleo‐currents and conglomerate components and the provenance of the strata around the graben indicate that it was Tethys Himalaya and High Himalaya. Electron spin resonance (ESR) dating and paleo‐magnetic dating suggest that the age of the strata ranges from ca. 1.2 Ma to ca. 8 Ma. Optically stimulated luminescence (OSL) dating showed that moraine in the graben mainly developed from around 181–109 ka (late Middle Pleistocene). Combining previous data about the Late Cenozoic strata in other basins, it is suggested that 8–15 Ma may be the initial rifting time. Together with sediment distribution and drainage system, the sedimentary evolution of Pagri could be divided into four stages. The graben rifted at around 15–8 Ma due to the eastern graben‐boundary fault resulting in the appearance of a paleolake. Following by a geologically quiet period about 8–2.5 Ma, the paleolake expanded from east to west at around 8–6 Ma reaching its maximum at ca. 6 Ma. Then, the graben was broken at about 2.5 Ma. At last, the development of the glacier separated the graben into two parts that were Pagri and Duoqing Co since the later stages of the Middle Pleistocene. The evolution process suggested that the former three stages were related to the tectonic movement, which determined the basement of the graben, while the last stage may have been influenced by glacial activity caused by climate change. [ABSTRACT FROM AUTHOR]