Accumulation of a Last Deglacial Gravel Layer at Diexi, Eastern Tibetan Plateau and its Possible Seismic Significance

Zhang, Siqi; Jiang, Hanchao; Fan, Jiawei; Xu, Hongyan; Shi, Wei; Guo, Qiaoqiao; Wei, Xiaotong

doi:10.3389/feart.2021.797732

Cited by 10 publications

(16 citation statements)

References 84 publications

(93 reference statements)

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“…Lacustrine paleoseismology can capture long continuous records of strong seismic shaking, which integrate the activity of all significant seismic sources in a region and allow a reliable determination of recurrence patterns (Moernaut, et al, 2018;Ghazoui et al, 2019;Lu et al, 2020;Oswald et al, 2021), including soft-sediment deformation (SSD, co-seismic) and seismites (postseismic). Among them, in-situ SSD structures can record a seismic event (Xu et al, 2015;Jiang et al, 2016;Lu et al, 2017Lu et al, , 2020Zhong et al, 2019;Zhang et al, 2021;Fan et al, 2022). Some seismites overlay the SSD, others lack an underlying SSD but are temporally correlated with a historic earthquake (Lu et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

A Continuous 13.3-Ka Paleoseismic Record Constrains Major Earthquake Recurrence in the Longmen Shan Collision Zone

et al. 2022

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Thrust collision zones with low slip rates along the plate boundary are significant areas of stress accumulation and prone to develop more destructive earthquakes with longer recurrence intervals. Such regions are often classified as low seismic risk if they lack continuous records of large earthquakes, such as the eastern Tibetan Plateau before the 2008 Mw 7.9 Wenchuan earthquake. Here, we provide a continuous seismic record in the Longmen Shan thrust fault zone spanning 13,000 years based on detailed investigation of the soft-sediment deformation structures and seismites in the Lixian lacustrine sequence. The recurrence time of large earthquakes (M ≥ 8.1) is 1,200 years, which is significantly shorter than the previous estimate of 2,000–6,000 years. The Maoxian-Wenchuan fault is the main fault that triggered the deformation in the Lixian lacustrine sediments. In addition, earthquake recurrence in the warm period is more frequent than that in the cold period, which should arouse our attention for the seismic study of tectonically active regions.

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Section: Introductionmentioning

confidence: 99%

A Continuous 13.3-Ka Paleoseismic Record Constrains Major Earthquake Recurrence in the Longmen Shan Collision Zone

et al. 2022

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“…Recent studies indicate that the upper Min River has poor vegetation coverage and most regions are fully exposed due to the strongly arid climate conditions (Jiang et al, 2015;Shi et al, 2020;Xu et al, 2020;Zhou et al, 2021). Thus, hillslope colluvium is the dominant sediment source to the upper Min River -especially in its middle and lower parts (Zhang et al, 2021) akin to those in drainage basins in many arid regions worldwide (Clapp et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Response of modern fluvial sediments to regional tectonic activity along the upper Min River, eastern Tibet

Shi

Jiang

et al. 2022

Earth Surf. Dynam.

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Abstract. The deposition of fluvial sediments in tectonically active areas is mainly controlled by tectonics, climate, and associated Earth surface processes; consequently, fluvial sediments can provide a valuable record of changes in regional climate and tectonic activity. In this study, we conducted a detailed analysis of the grain-size distribution in modern fluvial sediments from the upper Min River, eastern Tibet. These data, combined with information on regional climate, vegetation, hydrology, geomorphology, lithology, and fault slip rate, indicate that modern regional tectonic activity along upper Min River can be divided into three segments. Specifically, fluvial sediments in the Minjiangyuan–Diexi segment are dominated by silts (< 63 µm, 70.2 %), agreeing with low runoff, low rainfall, and high vegetation cover and revealing a windblown origin influenced by the arid and windy climate. These observations are consistent with the low hillslope angle and low relief, all indicating weak activity along the Minjiang Fault. The coarse-grained fraction (> 250 µm) of fluvial sediments in the Diexi–Wenchuan and Wenchuan–Dujiangyan segments increases stepwise downstream, although runoff and rainfall do not change significantly. These patterns correlate well with increases in both regional relief and hillslope angles. Together, these observations imply that regional tectonic activity along the Maoxian–Wenchuan Fault becomes more pervasive downstream along the Min River. The occurrence of well-sorted and well-rounded pebbles of fluvial sediments downstream of Dujiangyan must be related to the long-time scouring and sorting by rivers. This study marks the first development of a new research approach that can characterize regional tectonic activity by analysis of grain-size distribution of fluvial sediments collected from tectonically active regions.

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“…Recent studies indicate that the upper Min River has poor vegetation coverage and most regions are fully exposed due to the strongly arid climate conditions (Jiang et al, 2015;Xu et al, 2020;Shi et al, 2020;Wei et al, 2021;Zhou et al, 2021). Thus, hillslope colluvium is the dominant sediment source to the upper Min River -especially in its middle and lower segments (Zhang et al, 2021) -akin to those in drainage basins in many arid regions worldwide (Clapp et al, 2002).…”

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confidence: 99%

“…Tectonic activity influences the evolution of lacustrine sedimentary sequences by affecting the provenance supply (Najman, 2006;Jiang et al, 2022). Frequent earthquakes on the TP, as recorded by widely distributed soft sediment deformation (Wang et al, 2011;Xu et al, 2015;Jiang et al, 2016;Zhong et al, 2019;Zhang et al, 2021), caused repeated landslides that also represent another major source of sediment into the upper Min River (Dai et al, 2011;Xu et al, 2012Xu et al, , 2013. These landslides generated a large dust storm that deposited dust in nearby lakes (Jiang et al, 2014 and exposed large quantities of fine-grained sediment that had accumulated on mountain slopes, which were subsequently transported by wind to ancient lakes, documenting these seismic events (Whittaker et al, 2010;Liang and Jiang, 2017;Shi et al, 2022).…”

mentioning

confidence: 99%

“…Regional vegetation has clear vertical zonation, which mainly consists of smallleaf, arid shrubs at 1300-2200 m a.s.l., mixed broadleaf-conifer forests, evergreen and deciduous broad-leaved mixed forests at 2000-2800 m a.s.l., Picea and Abies forests at 2800-3600 m a.s.l., and alpine shrubs and meadows at > 3600 m a.s.l. (Ma et al, 2004;Zhang et al, 2008;Wei et al, 2021;Xu et al, 2020). There are two key factors that influence vegetation distribution and ecological conditions in the study area: the arid and windy climate, which has a large temperature difference between day and night, and tectonics activity characterized by frequent earthquakes (Lin, 2008;Wang et al, 2011).…”

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Response of modern fluvial sediments to regional tectonic activity along the Min River, Eastern Tibet

Shi

Jiang

et al. 2022

Preprint

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Abstract. The deposition of fluvial sediments in tectonically active areas is mainly controlled by tectonics, climate, and associated Earth surface processes; consequently, fluvial sediments can provide a valuable record of changes in regional climate and tectonic activity. In this study, we conducted a detailed analysis of the grain‒size distribution in modern fluvial sediments from the upper Min River, Eastern Tibet. These data were combined with regional information about climate, vegetation, hydrology, geomorphology, lithology, and fault slip rate, and together indicate that modern regional tectonic activity along upper Min River can be divided into three segments. Specifically, fluvial sediments in the segment Ⅰ are dominated by fine silts (<63 μm: 70.2 %), agreeing with a low‒runoff and low‒rainfall in this segment and revealing a windblown origin influenced by the arid and windy climate. These observations are consistent with the segment’s low hillslope angle and low relief, all indicating weak activity along the Minjiang Fault. The coarse‒grained fraction (>250 μm) of fluvial sediments in the segments Ⅱ ‒ Ⅲ increases in a stepwise fashion (A = 6.2 %, B = 19.4 %, C = 33.8 %) downstream, although runoff and rainfall do not change significantly from segment Ⅱ to segment Ⅲ. These patterns correlate well with an increase in both regional relief and hillslope angles. Together, these observations imply that regional tectonic activity along Maoxian‒Wenchuan Fault becomes more pervasive downstream along the Min River. Fluvial sediments in segment Ⅳ are well sorted and well rounded, which is expected due to significant increases in rainfall and runoff in this segment. This study marks the first development of a new and important research approach that can characterize regional tectonic activity by analysis of fluvial sediments collected from tectonically active regions, combined with regional conditions in geology and geography.

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Accumulation of a Last Deglacial Gravel Layer at Diexi, Eastern Tibetan Plateau and its Possible Seismic Significance

Cited by 10 publications

References 84 publications

A Continuous 13.3-Ka Paleoseismic Record Constrains Major Earthquake Recurrence in the Longmen Shan Collision Zone

A Continuous 13.3-Ka Paleoseismic Record Constrains Major Earthquake Recurrence in the Longmen Shan Collision Zone

Response of modern fluvial sediments to regional tectonic activity along the upper Min River, eastern Tibet

Response of modern fluvial sediments to regional tectonic activity along the Min River, Eastern Tibet

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