TY - JOUR
T1 - Three-dimensional P- and S-wave attenuation structures around the source region of the 2016 Kumamoto earthquakes 4. Seismology
AU - Komatsu, Masanao
AU - Takenaka, Hiroshi
AU - Oda, Hitoshi
N1 - Funding Information:
We are grateful to the editor, Dr. Stephen Bannister, and the three reviewers, Dr. Thomas Hearn and two anonymous reviewers, who provided us with constructive comments and suggestions that have improved this paper. We used the Hi-net velocity waveform data in the NIED and the source location from JMA-Unified Hypocenter Catalogs. We also used a computer program by Zhao et al. (, ) for the ray tracing. We used the elevation data by GSI 50 m mesh heights and GMT software (Wessel and Smith ). This study is partially supported by KAKENHI (26282105).
Publisher Copyright:
© 2017 The Author(s).
PY - 2017/12/1
Y1 - 2017/12/1
N2 - We investigate the three-dimensional P- and S-wave attenuation (Q P - 1 and Q S - 1) structures of the crust around the source region of the 2016 Kumamoto earthquakes, Japan. To estimate the attenuation structures, the path-averaged attenuation factor t ∗ is estimated from the amplitude decay rate of the P- and S-wave spectra corrected for the source spectrum. The (Q P - 1 and Q S 1) structures are estimated by tomography using t ∗ for the P- and S-waves, respectively. Several features are found in the attenuation structures as follows: In the source region, two high- Q P and high- Q S zones exist along the Futagawa and the Hinagu fault segments in the upper crust. The high- Q P and high- Q S zone along the Futagawa fault segment is found to include the large-slip area of the mainshock obtained from a source inversion study. In the lower crust, the low Q P is distributed beneath the entire source region. A low- Q P and low- Q S zone also exists beneath the Kuju and Aso volcanoes, which is consistent with the shallow limited depth extent of the seismogenic zone due to high temperature. The western edge of this zone adjoins the eastern edge of the high- Q P and high- Q S area, including the large-slip area.
AB - We investigate the three-dimensional P- and S-wave attenuation (Q P - 1 and Q S - 1) structures of the crust around the source region of the 2016 Kumamoto earthquakes, Japan. To estimate the attenuation structures, the path-averaged attenuation factor t ∗ is estimated from the amplitude decay rate of the P- and S-wave spectra corrected for the source spectrum. The (Q P - 1 and Q S 1) structures are estimated by tomography using t ∗ for the P- and S-waves, respectively. Several features are found in the attenuation structures as follows: In the source region, two high- Q P and high- Q S zones exist along the Futagawa and the Hinagu fault segments in the upper crust. The high- Q P and high- Q S zone along the Futagawa fault segment is found to include the large-slip area of the mainshock obtained from a source inversion study. In the lower crust, the low Q P is distributed beneath the entire source region. A low- Q P and low- Q S zone also exists beneath the Kuju and Aso volcanoes, which is consistent with the shallow limited depth extent of the seismogenic zone due to high temperature. The western edge of this zone adjoins the eastern edge of the high- Q P and high- Q S area, including the large-slip area.
KW - 2016 Kumamoto earthquakes
KW - Active volcano
KW - Attenuation structure
KW - Seismicity
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U2 - 10.1186/s40623-017-0683-6
DO - 10.1186/s40623-017-0683-6
M3 - Article
AN - SCOPUS:85026830066
VL - 69
JO - Earth, Planets and Space
JF - Earth, Planets and Space
SN - 1880-5981
IS - 1
M1 - 101
ER -