Seismic Imaging of Source Region in the 1976 Ms 7.8 Tangshan Earthquake Sequence and Its Implications for the Seismogenesis of Intraplate Earthquakes

2018 ◽  
Vol 108 (3A) ◽  
pp. 1302-1313 ◽  
Author(s):  
Zhiwei Li ◽  
Sidao Ni ◽  
Steven Roecker ◽  
Feng Bao ◽  
Xing Wei ◽  
...  
Keyword(s):  
Seismic Imaging ◽  
Source Region ◽  
Earthquake Sequence ◽  
Tangshan Earthquake ◽  
Intraplate Earthquakes

Active Faulting in Source Region of 2016–2017 Central Italy Event Sequence

2018 ◽  
Vol 34 (4) ◽  
pp. 1557-1583 ◽  
Author(s):  
Fabrizio Galadini ◽  
Emanuela Falcucci ◽  
Stefano Gori ◽  
Paolo Zimmaro ◽  
Daniele Cheloni ◽  
...  
Keyword(s):  
Source Region ◽  
Central Italy ◽  
Active Faults ◽  
Earthquake Sequence ◽  
Fault System ◽  
Fault Plane Solutions ◽  
Moment Tensors ◽  
Central Italy Earthquake ◽  
Finite Fault ◽  
Main Shocks

The Central Italy earthquake sequence produced three main shocks: M6.1 24 August, M5.9 26 October, and M6.5 30 October 2016. Additional M5–5.5 events struck this territory on 18 January 2017 in the Campotosto area. Fault plane solutions for the main shocks exhibit normal faulting (characteristic of crustal extension occurring in the inner central Apennines). Significant evidence, including hypocenter locations, strike and dip angles of the moment tensors, inverted finite fault models (using GPS, interferometric aperture radar, and ground motion data), and surface rupture patterns, all point to the earthquakes having been generated on the Mt. Vettore–Mt. Bove fault system (all three main shocks) and on the Amatrice fault, in the northern sector of the Laga Mountains (portion of 24 August event). The earthquake sequence provides examples of both synthetic and antithetic ruptures on a single fault system (30 October event) and rupture between two faults (24 August event). We describe active faults in the region and their segmentation and present understanding of the potential for linkages between segments (or faults) in the generation of large earthquakes.

The environment shear stress field for the 1976 Tangshan earthquake sequence

1994 ◽  
Vol 7 (4) ◽  
pp. 549-557 ◽  
Author(s):  
Pei-Shan Chen ◽  
Lei Xiao ◽  
Tong-Xia Bai ◽  
Xi-Li Wang
Keyword(s):  
Shear Stress ◽  
Stress Field ◽  
Earthquake Sequence ◽  
Tangshan Earthquake ◽  
Shear Stress Field

scholarly journals Visco-elastic stress triggering model of Tangshan earthquake sequence

2008 ◽  
Vol 21 (6) ◽  
pp. 585-597 ◽  
Author(s):  
Yong-ge Wan ◽  
Zheng-kang Shen ◽  
Yue-hua Zeng ◽  
Shu-zhong Sheng ◽  
Xiao-feng Xu
Keyword(s):  
Elastic Stress ◽  
Earthquake Sequence ◽  
Tangshan Earthquake ◽  
Stress Triggering ◽  
Triggering Model

Fluids Triggered the 2021 Mw 6.1 Yangbi Earthquake at an Unmapped Fault: Implications for the Tectonics at the Northern End of the Red River Fault

2022 ◽  
Author(s):  
Quan Sun ◽  
Zhen Guo ◽  
Shunping Pei ◽  
Yuanyuan V. Fu ◽  
Yongshun John Chen
Keyword(s):  
Source Region ◽  
High Stress ◽  
Red River ◽  
Earthquake Sequence ◽  
Rupture Zone ◽  
Double Difference ◽  
Data Set ◽  
Upward Migration ◽  
Velocity Models ◽  
Red River Fault

Abstract On 21 May 2021 a magnitude Mw 6.1 earthquake occurred in Yangbi region, Yunan, China, which was widely felt and caused heavy casualties. Imaging of the source region was conducted using our improved double-difference tomography method on the huge data set recorded by 107 temporary stations of ChinArray-I and 62 permanent stations. Pronounced structural heterogeneities across the rupture source region are discovered and locations of the hypocenters of the Yangbi earthquake sequence are significantly improved as the output of the inversion. The relocated Yangbi earthquake sequence is distributed at an unmapped fault that is almost parallel and adjacent (∼15 km distance) to the Tongdian–Weishan fault (TWF) at the northern end of the Red River fault zone. Our high-resolution 3D velocity models show significant high-velocity and low-VP/VS ratios in the upper crust of the rupture zone, suggesting the existence of an asperity for the event. More importantly, low-VS and high-VP/VS anomalies below 10 km depth are imaged underlying the source region, indicating the existence of fluids and potential melts at those depths. Upward migration of the fluids and potential melts into the rupture zone could have weakened the locked asperity and triggered the occurrence of the Yangbi earthquake. The triggering effect by upflow fluids could explain why the Yangbi earthquake did not occur at the adjacent TWF where a high-stress accumulation was expected. We speculate that the fluids and potential melts in the mid-to-lower crust might have originated either from crustal channel flow from the southeast Tibet or from local upwelling related to subduction of the Indian slab to the west.

scholarly journals Ground Motion and Seismic Source Aspects of the Canterbury Earthquake Sequence

2014 ◽  
Vol 30 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Brendon A. Bradley ◽  
Mark C. Quigley ◽  
Russ J. Van Dissen ◽  
Nicola J. Litchfield
Keyword(s):  
Ground Motion ◽  
Agricultural Land ◽  
Source Region ◽  
High Stress ◽  
Central Business District ◽  
Seismic Source ◽  
Vertical Displacement ◽  
Earthquake Sequence ◽  
River Channels ◽  
Canterbury Earthquake Sequence

This paper provides an overview of the ground motion and seismic source aspects of the Canterbury earthquake sequence. Common reported attributes among the largest earthquakes in this sequence are complex ruptures, large displacements per unit fault length, and high stress drops. The Darfield earthquake produced an approximately 30 km surface rupture in the Canterbury Plains with dextral surface displacements of several meters, and a subordinate amount of vertical displacement, impacting residential structures, agricultural land, and river channels. The dense set of strong ground motions recorded in the near-source region of all the major events in the sequence provides significant insight into the spatial variability in ground motion characteristics, as well as the significance of directivity, basin-generated surface waves, and nonlinear local site effects. The ground motion amplitudes in the 22 February 2011 earthquake, in particular, produced horizontal ground motion amplitudes in the Central Business District (CBD) well above those specified for the design of conventional structures.

RUPTURE DISTRIBUTION OF THE 1976 TANGSHAN EARTHQUAKE SEQUENCE INVERTED FROM GEODETIC DATA

2017 ◽  
Vol 60 (6) ◽  
pp. 583-601 ◽  
Author(s):  
WAN Yong-Ge ◽  
WAN Yong-Kui ◽  
JIN Zhi-Tong ◽  
SHENG Shu-Zhong ◽  
LIU Zhao-Cai ◽  
...  
Keyword(s):  
Geodetic Data ◽  
Earthquake Sequence ◽  
Tangshan Earthquake
Sign in / Sign up

Export Citation Format

Share Document