TY - JOUR
T1 - Coulomb stress perturbation after great earthquakes in the Sumatran subduction zone
T2 - Potential impacts in the surrounding region
AU - Qiu, Qiang
AU - Chan, Chung Han
N1 - Publisher Copyright:
© 2019 Elsevier Ltd
PY - 2019/8/15
Y1 - 2019/8/15
N2 - The Sumatran subduction zone has been seismically very active compared with other major subduction zones in the world. Since 2004, a sequence of large earthquakes ruptured along the trench, including the 2004 Mw 9.2 Sumatra-Andaman, the 2005 Mw 8.6 Nias-Simeulue, the 2007 Mw 8.4 Bengkulu, the 2010 Mw 7.8 Mentawai tsunami earthquakes and numerous moderate and small events. These earthquakes released stress over tens of seconds to minutes, disturbing the lithosphere and asthenosphere across a broad region. As earthquake-introduced stress disturbance can trigger tremendous aftershocks and sometimes precipitate large earthquakes in their vicinity, gaining a detailed picture of spatial and temporal stress evolution on the fault and its neighboring faults is crucial for seismic forecasting. Here, we have developed spatiotemporal Coulomb stress models for the Sumatran region, which includes the Sumatran subduction zone and the Sumatran fault, using a well-studied postseismic model. This postseismic model is constrained by decade-long time series of geodetic observations from the Sumatran GPS Array (SuGAr) and from tide gauge data in Southeast Asia. We show that Coulomb stress changes imparted by co- and post-seismic processes of previous great ruptures could well explain the temporal and spatial connection between seismicity and stress evolution. Most importantly, our results reveal that the stress in the Mentawai seismic gap of the Sumatran subduction zone was loaded by more than two bars. These stress perturbations could potentially trigger the rupture of the Mentawai seismic gap, which was already overdue in the last seismic cycle. Now, the likelihood for the failure of this gap is even higher than before 2004. We also find that along the Sumatran fault stress has increased to more than one bar, which may explain the surrounding seismicity. Consequently, we highlight the considerable seismic hazard and associated tsunami threat to the neighboring regions.
AB - The Sumatran subduction zone has been seismically very active compared with other major subduction zones in the world. Since 2004, a sequence of large earthquakes ruptured along the trench, including the 2004 Mw 9.2 Sumatra-Andaman, the 2005 Mw 8.6 Nias-Simeulue, the 2007 Mw 8.4 Bengkulu, the 2010 Mw 7.8 Mentawai tsunami earthquakes and numerous moderate and small events. These earthquakes released stress over tens of seconds to minutes, disturbing the lithosphere and asthenosphere across a broad region. As earthquake-introduced stress disturbance can trigger tremendous aftershocks and sometimes precipitate large earthquakes in their vicinity, gaining a detailed picture of spatial and temporal stress evolution on the fault and its neighboring faults is crucial for seismic forecasting. Here, we have developed spatiotemporal Coulomb stress models for the Sumatran region, which includes the Sumatran subduction zone and the Sumatran fault, using a well-studied postseismic model. This postseismic model is constrained by decade-long time series of geodetic observations from the Sumatran GPS Array (SuGAr) and from tide gauge data in Southeast Asia. We show that Coulomb stress changes imparted by co- and post-seismic processes of previous great ruptures could well explain the temporal and spatial connection between seismicity and stress evolution. Most importantly, our results reveal that the stress in the Mentawai seismic gap of the Sumatran subduction zone was loaded by more than two bars. These stress perturbations could potentially trigger the rupture of the Mentawai seismic gap, which was already overdue in the last seismic cycle. Now, the likelihood for the failure of this gap is even higher than before 2004. We also find that along the Sumatran fault stress has increased to more than one bar, which may explain the surrounding seismicity. Consequently, we highlight the considerable seismic hazard and associated tsunami threat to the neighboring regions.
KW - Coulomb stress
KW - Mentawai seismic gap
KW - Postseismic relaxation
KW - Sumatra
KW - Tsunami
KW - Volcano
UR - http://www.scopus.com/inward/record.url?scp=85066262914&partnerID=8YFLogxK
U2 - 10.1016/j.jseaes.2019.103869
DO - 10.1016/j.jseaes.2019.103869
M3 - 期刊論文
AN - SCOPUS:85066262914
SN - 1367-9120
VL - 180
JO - Journal of Asian Earth Sciences
JF - Journal of Asian Earth Sciences
M1 - 103869
ER -