TY - JOUR
T1 - Ambient noise tomography in the Naruko/Onikobe volcanic area, NE Japan
T2 - Implications for geofluids and seismic activity 4. Seismology
AU - Tamura, Jun
AU - Okada, Tomomi
N1 - Funding Information:
This study was supported by a grant from the Scientific Research Program on Innovative Areas, “Geofluids: Nature and Dynamics of Fluids in Subduction Zones” at the Tokyo Institute of Technology (21109002). We acknowledge JMA and NIED for providing the data. We are grateful to T. Matsuzawa, J. Nakajima, N. Uchida, M. Yamamoto, T. Sato, S. Hori, K. Tachibana, T. Kono, S. Hirahara, T. Nakayama, S. Suzuki, T. Demachi, T. Kaida, and Y. Chiba for the operation of the Naruko array.
Publisher Copyright:
© 2016 Tamura and Okada.
PY - 2016/12/1
Y1 - 2016/12/1
N2 - To understand the earthquake generation in volcanic areas, it is important to investigate the presence of geofluids in the uppermost crust. We applied ambient noise tomography to the Naruko/Onikobe volcanic area and constructed a detailed 3-D S-wave velocity (V s) model using continuous records from a dense seismic network and surrounding stations. The low-velocity zones were found beneath Naruko Volcano, Onikobe Caldera, and Mt. Kurikoma. The low-velocity zone beneath Onikobe Caldera may correspond to a magma reservoir, which is also characterized by surrounding S-wave reflectors. The molten magma originates from the upwelling flows in the mantle wedge. We also conducted the relocation of aftershocks of the 2008 Iwate-Miyagi Nairiku earthquake by double-difference tomography based on the obtained velocity model. Beneath Mt. Kurikoma, aftershock distribution delineates one of the unfavorably oriented fault planes of the main shock, which implies that the low-velocity zone around the fault plane is related to the presence of overpressurized fluid.
AB - To understand the earthquake generation in volcanic areas, it is important to investigate the presence of geofluids in the uppermost crust. We applied ambient noise tomography to the Naruko/Onikobe volcanic area and constructed a detailed 3-D S-wave velocity (V s) model using continuous records from a dense seismic network and surrounding stations. The low-velocity zones were found beneath Naruko Volcano, Onikobe Caldera, and Mt. Kurikoma. The low-velocity zone beneath Onikobe Caldera may correspond to a magma reservoir, which is also characterized by surrounding S-wave reflectors. The molten magma originates from the upwelling flows in the mantle wedge. We also conducted the relocation of aftershocks of the 2008 Iwate-Miyagi Nairiku earthquake by double-difference tomography based on the obtained velocity model. Beneath Mt. Kurikoma, aftershock distribution delineates one of the unfavorably oriented fault planes of the main shock, which implies that the low-velocity zone around the fault plane is related to the presence of overpressurized fluid.
KW - 2008 Iwate-Miyagi Nairiku earthquake
KW - Ambient noise tomography
KW - Geofluids
KW - Naruko Volcano
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U2 - 10.1186/s40623-016-0380-x
DO - 10.1186/s40623-016-0380-x
M3 - Article
AN - SCOPUS:84954544543
VL - 68
JO - Earth, Planets and Space
JF - Earth, Planets and Space
SN - 1343-8832
IS - 1
M1 - 5
ER -