Baoqi Ma

• Insititute of Crustal Dynamics, China Earthquake Administration

The Sichuan-Yunnan block is a tectonically active region in China, with frequent large earthquakes occurring in and around it. Despite most earthquakes being concentrated along boundary faults, intraplate faults also have the potential to generate damaging earthquakes. Remote sensing makes it possible to identify these potential earthquake source f...

Long paleoearthquake series are crucial for understanding the recurrence patterns of active faults and evaluating the seismic hazards of faults. In this study, the first semiquantitative evaluation of paleoearthquake events from trenches was applied to normal faults, and classification criteria for identifying paleoearthquakes in trenches on normal...

The slip rate is a fundamental kinematic parameter of active faults. Traditional methods using fault scarps or trenches may produce inaccurate estimates of a fault’s vertical slip rate. A normal fault’s vertical slip rate requires constraints from the hanging wall and footwall. Here, the vertical slip rate at each measuring point along the fault wa...

The activity of major active faults around the Ordos Block is of great interest to seismologists, as at least four M ≥ 8 earthquakes have been recorded. However, the Linhe Basin, which has the thickest Cenozoic sediments, has no record of large earthquakes. Does this basin have the structural conditions required for large earthquakes? The northern...

The Wuhai Basin is located in the northwestern corner of the Ordos Block. Analyzing the geometry, along with the kinematic and dynamic characteristics of the boundary fault, the Zhuozishan West Piedmont Fault (ZWPF), will elucidate the regional tectonic environment and guide earthquake prevention and disaster reduction projects. Six representative...

Active fault is one of the major problems in engineering geology research. The ground ruptures generated by the activity of the faults are great hazards to the projects. The location and activity of active fractures have a major impact on the site selection of railways, highways, water conservancy, and hydropower projects. During the construction o...

Few studies have been conducted on the activity of the Mengzi fault system, which is located to the southeast of the Sichuan-Yunnan block. The Mengzi fault is distributed along the eastern margin of the Mengzi basin. However, little is known about the location, length, and activity of the fault or the occurrence of paleo-earthquakes during the late...

Studying the faults in Wuhai Basin, which is located in the northwestern corner of the Ordos Block in China, can not only guide earthquake-safe construction in the region, but also provide a greater understanding of the structure of the Wuhai Basin and the dynamic environment of Northwestern Ordos Block. In this study, we effectively detected the Y...

The two eastern segments of the Sertengshan piedmont fault have moved considerably since the Holocene. Several paleoseismic events have occurred along the fault since 30 ka BP. Paleoearthquake studies have been advanced by digging new trenches and combining the results with the findings of previous studies. Comprehensive analyses of the trenches re...

Ground fissures are a geological hazard with complex formation mechanisms. Increasing amounts of human activity have created more ground fissures, which can destroy buildings and threaten human security. Some ground fissures indicate potentially devastating earthquakes, so we must pay attention to these hazards. This paper documents recently discov...

The vertical slip rate of a normal fault is one of the most important parameters for evaluating its level of activity. The Sertengshan piedmont fault has been studied since the 1980s, but its absolute vertical slip rate has not been determined. In this paper, we calculate the displacements of the fault by measuring the heights of piedmont terraces...

The late Quaternary activity of Yushu segment is poorly understood compared with other segments within Ganzi-Yushu Fault system. We focused on the Batang Fault, a major branch fault of the Yushu segment. Interpretation of remote sensing images and field investigations reveal that this fault has a clear geomorphic expression which is characterized b...

The Yushu segment of the Ganzi-Yushu fault system (central Tibet plateau) is mainly composed by the Yushu fault and the Batang fault. The 2010 Ms 7.1 Yushu earthquake occurred on the Yushu fault, causing huge loss of lives and widespread damages to the densely populated Yushu area. So far, much effort has been devoted to the surface rupture and pal...

This paper reports silt pellets found at the terminus of the east branch of Glacier No. 1, Tian Shan, Northwestern China. These pellets of approximately 1 mm in diameter appeared as layers on glacier surface. Two pellet samples were collected for microscope examination, grain-size measurement, and geochemical analysis to understand their nature, or...

This paper presents a preliminary study on lake-level fluctuations since the Last Glaciation in Selin Co (lake), Central Tibet, by dating four groups of beach ridges using optically stimulated luminescence (OSL). The highest/oldest beach ridge group (>100 m higher than the current lake level) is dated back to 67.9 ± 2.4 ka BP, corresponding to the...

In-situ measurement of clast fabric within till and other sediment was performed at locations in Hayisa (HY), Upper-Wangfeng (UW), Lower-Wangfeng (LW) and Balatigou (BL), in the upper Urumqi River in the Tian Shan of NW China. Subglacial tills have stronger fabric of both a-axis and a–b-plane than supraglacial till. This can be explained as a resul...

Traditional theories of geographical cycle and pediplain cannot describe correctly the development of planation surfaces in karst regions. Authors, therefore, put forward conception of karst planation and karst planation surface, suggesting that karst planation is another type of planation process characterized by chemical erosion and transformatio...