Source model of an earthquake doublet that occurred in a pull-apart basin along the Sumatran fault, Indonesia

Details Source model of an earthquake doublet that occurred in a pull-apart basin along the Sumatran fault, Indonesia Source model of an earthquake doublet that occurred in a pull-apart basin along the Sumatran fault, Indonesia

Apr 2010

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010geoji.181..141n&link_type=abstract

Geophysical Journal International, Volume 181, Issue 1, pp. 141-153.

Astronomy and Astrophysics

Astronomy

1

Earthquake Source Observations, Earthquake Interaction, Forecasting, And Prediction, Continental Tectonics: Strike-Slip And Transform, Dynamics And Mechanics Of Faulting, Dynamics: Seismotectonics, Rheology And Friction Of Fault Zones

Scientific paper

On 2007 March 6, an earthquake doublet occurred along the Sumatran fault, Indonesia. The epicentres were located near Padang Panjang, central Sumatra, Indonesia. The first earthquake, with a moment magnitude (Mw) of 6.4, occurred at 03:49 UTC and was followed two hours later (05:49 UTC) by an earthquake of similar size (Mw = 6.3). We studied the earthquake doublet by a waveform inversion analysis using data from a broadband seismograph network in Indonesia (JISNET). The focal mechanisms of the two earthquakes indicate almost identical right-lateral strike-slip faults, consistent with the geometry of the Sumatran fault. Both earthquakes nucleated below the northern end of Lake Singkarak, which is in a pull-apart basin between the Sumani and Sianok segments of the Sumatran fault system, but the earthquakes ruptured different fault segments. The first earthquake occurred along the southern Sumani segment and its rupture propagated southeastward, whereas the second one ruptured the northern Sianok segment northwestward. Along these fault segments, earthquake doublets, in which the two adjacent fault segments rupture one after the other, have occurred repeatedly. We investigated the state of stress at a segment boundary of a fault system based on the Coulomb stress changes. The stress on faults increases during interseismic periods and is released by faulting. At a segment boundary, on the other hand, the stress increases both interseismically and coseismically, and may not be released unless new fractures are created. Accordingly, ruptures may tend to initiate at a pull-apart basin. When an earthquake occurs on one of the fault segments, the stress increases coseismically around the basin. The stress changes caused by that earthquake may trigger a rupture on the other segment after a short time interval. We also examined the mechanism of the delayed rupture based on a theory of a fluid-saturated poroelastic medium and dynamic rupture simulations incorporating a rheological velocity hardening effect. These models of the delayed rupture can qualitatively explain the observations, but further studies, especially based on the rheological effect, are required for quantitative studies.

Affiliated with

Also associated with

No associations

Rating

Source model of an earthquake doublet that occurred in a pull-apart basin along the Sumatran fault, Indonesia does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Source model of an earthquake doublet that occurred in a pull-apart basin along the Sumatran fault, Indonesia, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Source model of an earthquake doublet that occurred in a pull-apart basin along the Sumatran fault, Indonesia will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1315197