TY - JOUR
T1 - Acceleration of regional plate subduction beneath Kanto, Japan, after the 2011 Tohoku-oki earthquake
AU - Uchida, Naoki
AU - Asano, Youichi
AU - Hasegawa, Akira
N1 - Publisher Copyright:
©2016. American Geophysical Union. All Rights Reserved.
PY - 2016/9/16
Y1 - 2016/9/16
N2 - Two oceanic plates (the Pacific (PA) and Philippine Sea (PH)) subduct beneath the land plate, and they forms deeper (PH-PA) and shallower (land-PH) plate boundaries beneath Kanto. Remarkably enhanced seismicity was observed in the densely populated area after the 2011 Tohoku-oki earthquake, which cannot simply be explained by the southern expansion of the postseismic slip of the earthquake. We examine interplate repeating earthquakes to constrain the relative plate motion across aseismically slipping faults. The repeater slip rates show creep rates in the deeper and shallower boundaries, respectively, increased to 2.4–6.6 times and 1.3–6.2 times the pre-Tohoku-oki rates. In addition, the repeater slip directions show no change larger than 4° in the deeper boundary. The interplate creep rates and slip directions suggest that regional movements of both the two plates had accelerated. They probably caused the seismicity increase, frequent slow slips on the shallower boundary, and enhanced probability of larger earthquakes.
AB - Two oceanic plates (the Pacific (PA) and Philippine Sea (PH)) subduct beneath the land plate, and they forms deeper (PH-PA) and shallower (land-PH) plate boundaries beneath Kanto. Remarkably enhanced seismicity was observed in the densely populated area after the 2011 Tohoku-oki earthquake, which cannot simply be explained by the southern expansion of the postseismic slip of the earthquake. We examine interplate repeating earthquakes to constrain the relative plate motion across aseismically slipping faults. The repeater slip rates show creep rates in the deeper and shallower boundaries, respectively, increased to 2.4–6.6 times and 1.3–6.2 times the pre-Tohoku-oki rates. In addition, the repeater slip directions show no change larger than 4° in the deeper boundary. The interplate creep rates and slip directions suggest that regional movements of both the two plates had accelerated. They probably caused the seismicity increase, frequent slow slips on the shallower boundary, and enhanced probability of larger earthquakes.
KW - Kanto earthquake
KW - Philippine Sea plate
KW - Tohoku-oki earthquake
KW - aseismic slip
KW - plate motion
KW - repeating earthquake
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U2 - 10.1002/2016GL070298
DO - 10.1002/2016GL070298
M3 - Article
AN - SCOPUS:84987668295
VL - 43
SP - 9002
EP - 9008
JO - Geophysical Research Letters
JF - Geophysical Research Letters
SN - 0094-8276
IS - 17
ER -