TY - JOUR
T1 - Tsunamis from strike-slip earthquakes in theWharton Basin, northeast Indian Ocean
T2 - March 2016Mw7.8 event and its relationship with the April 2012Mw 8.6 event
AU - Heidarzadeh, Mohammad
AU - Harada, Tomoya
AU - Satake, Kenji
AU - Ishibe, Takeo
AU - Takagawa, Tomohiro
N1 - Publisher Copyright:
© The Authors 2017.
PY - 2017/12/1
Y1 - 2017/12/1
N2 - The Wharton Basin, off southwest Sumatra, ruptured to a large intraplate left-lateral strikeslip Mw 7.8 earthquake on 2016 March 2. The epicentre was located ~800 km to the south of another similar-mechanism intraplate Mw 8.6 earthquake in the same basin on 2012 April 11. Small tsunamis from these strike-slip earthquakes were registered with maximum amplitudes of 0.5-1.5 cm on DARTs and 1-19 cm on tide gauges for the 2016 event, and the respective values of 0.5-6 and 6-40 cm for the 2012 event. By using both teleseismic body waves and tsunami observations of the 2016 event, we obtained optimum slip models with rupture velocity (Vr ) in the range of 2.8-3.6 kms-1 belonging to both EWand NS faults.While the EW fault plane cannot be fully ruled out, we chose the best model as the NS fault plane with a Vr of 3.6 km s-1, a maximum slip of 7.7 m and source duration of 33 s. The tsunami energy period bands were 4-15 and 7-24 min for the 2016 and 2012 tsunamis, respectively, reflecting the difference in source sizes. Seismicity in the Wharton Basin is dominated by large strike-slip events including the 2012 (Mw 8.6 and 8.2) and 2016 (Mw 7.8) events, indicating that these events are possible tsunami sources in theWharton Basin. Cumulative number and cumulative seismic-moment curves revealed that most earthquakes are of strike-slip mechanisms and the largest seismic-moment is provided by the strike-slip earthquakes in this basin.
AB - The Wharton Basin, off southwest Sumatra, ruptured to a large intraplate left-lateral strikeslip Mw 7.8 earthquake on 2016 March 2. The epicentre was located ~800 km to the south of another similar-mechanism intraplate Mw 8.6 earthquake in the same basin on 2012 April 11. Small tsunamis from these strike-slip earthquakes were registered with maximum amplitudes of 0.5-1.5 cm on DARTs and 1-19 cm on tide gauges for the 2016 event, and the respective values of 0.5-6 and 6-40 cm for the 2012 event. By using both teleseismic body waves and tsunami observations of the 2016 event, we obtained optimum slip models with rupture velocity (Vr ) in the range of 2.8-3.6 kms-1 belonging to both EWand NS faults.While the EW fault plane cannot be fully ruled out, we chose the best model as the NS fault plane with a Vr of 3.6 km s-1, a maximum slip of 7.7 m and source duration of 33 s. The tsunami energy period bands were 4-15 and 7-24 min for the 2016 and 2012 tsunamis, respectively, reflecting the difference in source sizes. Seismicity in the Wharton Basin is dominated by large strike-slip events including the 2012 (Mw 8.6 and 8.2) and 2016 (Mw 7.8) events, indicating that these events are possible tsunami sources in theWharton Basin. Cumulative number and cumulative seismic-moment curves revealed that most earthquakes are of strike-slip mechanisms and the largest seismic-moment is provided by the strike-slip earthquakes in this basin.
KW - Earthquake source observations
KW - Fourier analysis
KW - Indian Ocean
KW - Numerical modelling
KW - Seismicity and tectonics
KW - Tsunamis
UR - http://www.scopus.com/inward/record.url?scp=85035093317&partnerID=8YFLogxK
U2 - 10.1093/gji/ggx395
DO - 10.1093/gji/ggx395
M3 - Article
AN - SCOPUS:85035093317
SN - 0956-540X
VL - 211
SP - 1601
EP - 1612
JO - Geophysical Journal International
JF - Geophysical Journal International
IS - 3
ER -