Abstract
We constructed the rupture process model for the 2016 Kumamoto, Japan, earthquake from broadband teleseismic body waveforms (P-waves) by using a novel waveform inversion method that takes into account the uncertainty of Green’s function. The estimated source parameters are: seismic moment = 5.1 × 1019 Nm (Mw = 7.1), fault length = 40 km, and fault width = 15 km. The mainshock rupture mainly propagated northeastward from the epicenter, for about 30 km, along an active strike-slip fault. The rupture propagation of the mainshock decelerated and terminated near the southwest side of the Aso volcano; the aftershock activity was low around the northeastern edge of the major slip area. Our results suggest that the rupture process of the mainshock and the distribution of aftershocks were influenced by the high-temperature area around the magma chamber of Mt. Aso.
Highlights
A large and destructive earthquake (MJMA 7.3) occurred on April 15, 2016 [Coordinated Universal Time (UTC)], in Kumamoto region, Kyushu Island, Japan
The origin time of the earthquake was April 16, 2016, 01:25 [Japan Standard Time (JST)], its epicenter was located at 32.76°N, 130.76°E, and its hypocentral depth was 12 km, as determined by the Japan Meteorological Agency (JMA)
The aftershock distribution and a focal mechanism determined in this study (Fig. 1a) indicate that the 2016 Kumamoto earthquake occurred along an active strikeslip fault, known as the Futagawa fault (Fig. 1a; Research Group for Active Faults of Japan 1991), which belongs to the Oita–Kumamoto Tectonic Line (OKTL; Fig. 1b) (e.g., Kamata and Kodama 1994) and is adjacent to the major shear zone in Kyushu (Matsumoto et al 2015)
Summary
A large and destructive earthquake (MJMA 7.3) occurred on April 15, 2016 [Coordinated Universal Time (UTC)], in Kumamoto region, Kyushu Island, Japan. The geologic structure, which includes the Aso volcano, locates in the central part of the OKTL and might have contributed to the complex rupture process during foreshocks, mainshock, and aftershocks. The source model of the mainshock, in particular, may help to understand the seismicity evolution during the 2016 Kumamoto earthquake sequence in its geologic context. We discuss the relationship between the rupture process of the mainshock, seismicity, and the geologic structure around the Aso volcano. Understanding the relationship between seismicity and crustal geophysics (e.g., Hauksson 2011), in particular the crustal thermal structure (Enescu et al 2009), may help in a better assessment of seismic hazard
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
