Velocity structure of the upper crust and its correlation with earthquake swarms activity in Laizhou Bay and its adjacen
- PDF / 5,818,552 Bytes
- 16 Pages / 439.37 x 666.142 pts Page_size
- 89 Downloads / 165 Views
Velocity structure of the upper crust and its correlation with earthquake swarms activity in Laizhou Bay and its adjacent areas, China Jinchao Shen1,2 · Minmin Xu3 · Shicheng Li4 · Huiyong Yin2 Received: 4 October 2019 / Accepted: 20 July 2020 © Akadémiai Kiadó 2020
Abstract This study used the double-difference seismic tomography method to obtain the upper crustal velocity structure in Laizhou Bay and its adjacent areas (LBAA). We found that the horizontal and vertical distributions of the earthquakes after relocation in earthquake swarms are more concentrative than that before relocation. The lateral heterogeneity of crustal velocity structure near the surface in the LBAA is weak, and the low-velocity sedimentary caprocks are developed in most areas except for the Jiaobei uplift. The velocity structure in 5–25 km depth range is highly heterogeneity, which is closely related to different tectonic units. The local uplift tectonic units in Jiyang depression show high-velocity anomalies and should have deep crustal media properties. The high-velocity anomalies under the crust of Tancheng–Lujiang fault zone and the northern Laizhou Bay indicate the properties of upwelling mantle material media. Earthquake swarms activity in the study area are mainly concentrated in the high-velocity interlayer of the upper crust and its periphery. Compared with the relatively stable high-velocity body at the bottom crust, the location of high-velocity interlayer in the study area is more prone to earthquakes under the combined action of gravity and tectonic stress. Keywords Velocity structure · Earthquake swarm activity · The double-difference seismic tomography
* Jinchao Shen [email protected] 1
Jinan Earthquake Monitoring Center, 8577 Lvyou Road, Jinan 250000, China
2
Shandong Key Laboratory of Depositional Mineralization and Sedimentary Mineral, College of Earth Science and Engineering, Shandong University of Science and Technology, Qingdao 266590, China
3
Shandong Academy of Environmental Sciences Co., Ltd, Jinan 250000, China
4
Department of Land Resource Management, School of Public Administration, China University of Geosciences, Wuhan 430074, China
13
Vol.:(0123456789)
Acta Geodaetica et Geophysica
1 Introduction The LBAA is located in the north of Shandong Province, China, and the research area of LBAA covers Laizhou Bay and its southern adjacent inland area (118.2°–121.4°E, 36.6°–38.4°N). Due to the tectonic activity of the Tancheng–Lujiang fault zone in the eastern China and the western Pacific subduction Plate, the tectonic environment of the LBAA is complex, and it is also an earthquake-prone area (Fukao et al. 1992; Fu et al. 2004; Zhao 2004; Wang et al. 2008; Lei 2012; Lv et al. 2016; Wang et al. 2017). Changdao earthquake swarm (Liu et al. 2018; Shen et al. 2019a), Laizhou earthquake swarm (Zheng et al. 2015), Kenli earthquake swarm and the northern Laizhou bay earthquake concentrating area in study area are the most typical seismicity. Changdao earthquake swarm is located in the eastern sea area o
Data Loading...
