open access

https://hdl.handle.net/2115/53503

An interpretation of tsunami earthquake based on a simple dynamic model : Failure of shallow megathrust earthquake

英語

Numerical experiment

2013-04-28

Wiley-Blackwell

Geophysical Research Letters

40(8)

1523-1527

The 2011 Tohoku earthquake demonstrated that extremely large seismic slip can occur at shallow plate interfaces in subduction zones. The large slip area for the Tohoku earthquake included the source region of a tsunami earthquake. We performed dynamic rupture simulations using simplified fault models and the mechanism of thermal fluid pressurization. We found that small fluctuations of initial shear stress near a trench, within 1 MPa, lead to differences in seismic moment release greater than two orders of magnitude. In addition, we performed another experiment varying rupture nucleation sizes and obtained similar acute sensitivities of parameters. Moderate slip events with trapezoidal (flat‒topped) source time functions appear to occupy a transition position, between shallow megathrust earthquakes with surface rupture and smaller ordinary earthquakes without surface rupture. We interpret this result as representing the differences in interplate slip between shallow megathrust earthquakes, tsunami (moderate) earthquakes, and non‒tsunami (ordinary) earthquakes, on the basis of seismic observations.

学術雑誌論文

Version of Record

Copyright 2013 American Geophysical Union

0094-8276

1944-8007

AA00657102