Seismicity of the Denali-Totschunda Fault Zone in Central Alaska (1912-1988) and Its Relation to the 2002 Denali Fault Earthquake Sequence

2004 ◽  
Vol 94 (6B) ◽  
pp. S132-S144 ◽  
Author(s):  
D. I. Doser
Keyword(s):  
Fault Zone ◽  
Earthquake Sequence ◽  
Denali Fault

scholarly journals Focal Mechanism and Seismogenic Structure of the MS 5.1 Qingbaijiang Earthquake on February 3, 2020, Southwestern China

2021 ◽  
Vol 9 ◽  
Author(s):  
Min Zhao ◽  
Feng Long ◽  
Guixi Yi ◽  
MingJian Liang ◽  
Jiangtao Xie ◽  
...  
Keyword(s):  
Fault Zone ◽  
Focal Mechanism ◽  
Earthquake Sequence ◽  
Southwestern China ◽  
Joint Analysis ◽  
Focal Mechanism Solution ◽  
Inversion Method ◽  
Seismogenic Structure ◽  
Initial Rupture ◽  
Hypocentral Distribution

The 3 February 2020 MS 5.1 Qingbaijiang earthquake, southwestern China, is the closest recorded MS ≥ 5.0 event to downtown Chengdu City to date, with an epicentral distance of only 38 km. Here we analyze seismic data from the Sichuan and Chengdu regional seismic networks, and employ a multi-stage location method to relocate the earthquakes that have occurred along the central and northern segments of the Longquanshan fault zone since 2009, including the MS 5.1 Qingbaijiang earthquake sequence, to investigate the seismogenic structure of the region. The relocation results indicate that the seismicity along the central and northern segments of the Longquanshan fault zone has occurred mainly along the eastern branch since 2009, with the hypocentral distribution along a vertical cross-section illustrating a steep, NW-dipping parallel imbricate structure. The terminating depth of the eastern branch is about 12 km. The distribution of the MS 5.1 Qingbaijiang earthquake sequence is along the NE–SW-striking Longquanshan fault zone. The aftershock focal depths are in the 3–6 km range, with the mainshock located at 104.475°E, 30.73°N. Its initial rupture depth of 5.2 km indicates that the earthquake occurred above the shallow decollement layer of the upper crust in this region. The hypocentral distribution along the long axis of the aftershock area highlights that this earthquake sequence occurred along a fault dipping at 56° to the NW. Our surface projection of the inferred fault plane places it near the eastern branch of the Longquanshan fault zone. We infer the MS 5.1 mainshock to be a thrust faulting event based on the focal mechanism solution via the cut-and-paste waveform inversion method, with strike/dip/rake parameters of 22°/36°/91° and 200°/54°/89° obtained for nodal planes I and II, respectively. We identify that the seismogenic fault of the MS 5.1 Qingbaijiang earthquake lies along the eastern branch of the Longquanshan fault zone, and nodal plane II represents the coseismic rupture plane, based on a joint analysis of the event relocation results, mainshock focal mechanism, and regional geological information. Our study provides vital information for assessing the seismic hazard of the Longquanshan fault zone near Chengdu City.

scholarly journals Thermotectonic History of the Kluane Ranges and Evolution of the Eastern Denali Fault Zone in Southwestern Yukon, Canada

Tectonics ◽  
2019 ◽  
Vol 38 (8) ◽  
pp. 2983-3010 ◽  
Author(s):  
Robert G. McDermott ◽  
Alexis K. Ault ◽  
Jonathan Saul Caine ◽  
Stuart N. Thomson
Keyword(s):  
Fault Zone ◽  
Denali Fault ◽  
History Of

Tectonic Context and Possible Triggering of the 2019–2020 Puerto Rico Earthquake Sequence

2022 ◽  
Author(s):  
Marjolein Blasweiler ◽  
Matthew W. Herman ◽  
Fenna Houtsma ◽  
Rob Govers
Keyword(s):  
Puerto Rico ◽  
Fault Zone ◽  
Plate Boundary ◽  
Strike Slip ◽  
Global Navigation Satellite Systems ◽  
Earthquake Sequence ◽  
Motion Direction ◽  
Lateral Strike Slip ◽  
Coulomb Stress Changes ◽  
Stress Changes

Abstract An historically unprecedented seismic moment was released by crustal events of the 2019–2020 earthquake sequence near southwest Puerto Rico. The sequence involved at least two, and perhaps three interacting fault systems. The largest Mw 6.4 event was likely triggered by left lateral strike-slip events along the eastern extension of the North Boquerón Bay-Punta Montalva fault zone. The mainshock occurred in a normal fault zone that extends into a region where previous studies documented extensional deformation, beyond the Ponce fault and the Bajo Tasmanian fault. Coulomb stress changes by the mainshock may have triggered further normal-faulting aftershocks, left lateral strike-slip events in the region where these two fault zones interacted, and possibly right lateral strike-slip aftershocks along a third structure extending southward, the Guayanilla fault zone. Extension directions of the seismic sequence are consistently north-northwest–south-southeast-oriented, in agreement with the Global Navigation Satellite Systems-inferred motion direction of eastern Hispaniola relative to western Puerto Rico, and with crustal stress estimates for the overriding plate boundary zone.

Sign in / Sign up

Export Citation Format

Share Document