Special Issue: Special Section for the 2007 Noto Hanto Earthquake (1)
- Letter
- Open Access
- Published:
Gravity anomalies and the geologic block structures in and around the aftershock area of the 2007 Noto Hanto Earthquake
Earth, Planets and Space volume 60, pages 111–115 (2008)
Abstract
The 2007 Noto Hanto Earthquake occurred on 25 March. We have constructed a detailed gravity anomaly map over the Noto peninsula. Four block boundaries which are identified by morphological/geological studies are also recognized on the gravity anomaly map. Various other observations indicate that the mainshock ruptured only one of the blocks, the Kuwatsuka block, although aftershocks are distributed over two blocks, the Kuwatsuka and the Saruyama blocks. The Bouguer anomalies over the Kuwatsuka block are relatively high compared to those of the Saruyama block, i.e. the basement depth of the Kuwatsuka block is shallower than that of the Saruyama block. This difference in the basement depth is consistent with the deformation pattern observed by SAR interferometry. At the block boundary, an offset is recognized in the aftershock distribution. Based on the relationships among the gravity anomalies, the geologic structures, the aftershock distribution and the source fault, we propose that the rupture size of the earthquake was constrained by the block structure in this region.
References
Active Fault Research Group, Active Faults in Japan: sheet map and inventories (Revised ed.), 437 pp., University of Tokyo Press, Tokyo, 1991 (in Japanese).
Advanced Industrial Science and Technology, http://unit.aist.go.jp/actfault/katsudo/jishin/notohanto/report/070403.html, 2007.
Earthquake Research Institute, http://www.eri.u-tokyo.ac.jp/topics/noto20070325/20070325satow2.html, 2007.
Fukushima, Y., T. Ozawa, and M. Hashimoto, Crustal deformation analysis using SAR interferometry on the 2007 Noto Hanto earthquake, Abstract for Japan Geoscience Union Joint Meet., Z255-P019, 2007.
Geographycal Survey Institute of Japan, http://vldb.gsi.go.jp/sokuchi/gravity/grvsearch/gravity.pl, 2002.
Geographycal Survey Institute of Japan, http://gsi.go.jp/WNEW/PRESS-RELEASE/2007/0412html, 2007.
Geological Survey of Japan, Gravity CD-ROM of Japan, Digital Geo-science Map P-2, edited by Geological Survey of Japan, 2000.
Hiramatsu, Y., K. Moriya, T. Kamiya, and M. Kato, Fault model of the 2007 Noto Hanto earthquake estimated from coseismic deformation obtained by the distribution of midlittoral and infralittoral organisms and GPS, Earth Planets Space, 2007 (submitted).
Honda, R. and Y. Kono, Synthesized Land and Sea 50 M Digital Elevation Model and Gravimetric Terrain Correction in and around the Japanese Islands, J. Geod. Soc. Japan, 51, 33–44, 2005 (in Japanese with English abstract).
Horikawa, H., Source process of the 2007 Noto-Hanto earthquake (M6.9), Abstract for Japan Geoscience Union Joint Meet., Z255-P008, 2007.
Hoshiba, M., Outline of the Noto Hanto Earthquake in 2007, Abstract for Japan Geoscience Union Joint Meet., Z255-P001, 2007.
Japan Aerospace Exploration Agency, http://www.jaxa.jp/press/2007/04/20070412_daichi_j.html, 2007.
Kaseno, Y., Geology of Ishikawa-ken, Japan (with Geological Maps), 321 pp, Ishikawa prefecture and Hokuriku Geology Institute, Ishikawa, 1993 (in Japanese).
Katagawa, H., M. Hamada, S. Yoshida, H. Kadosawa, A. Mitsuhashi, Y. Kono, and Y. Kinugasa, Geological Development of the West Sea Area of the Noto Peninsula District in the Neogene Tertiary to Quaternary, Central Japan, J. Geogr., 114, 791–810, 2005 (in Japanese with English abstract).
Kono, Y. and N. Furuse, 1 in 1 Million Scale Gravity anomalies over the Japanese Islands, 79 pp., University of Tokyo Press, Tokyo, 1989 (in Japanese).
Kono, Y., R. Honda, and M. Hamada, Gravity anomalies around middle part of the Noto peninsula, Abstract for Seism. Soc. Japan 2006 fall meeting, D58, 2006.
Kono, Y., R. Honda, M. Hamada, and H. Katagawa, Gravity anomalies and geological structure of central part of the Noto Peninsula, Zisin, (in preparation).
Ohta, Y., T. Matsuda, and K. Hirakawa, Active faults in Noto Peninsula, Central Japan, The Quaternary Research, 15, 109–128, 1976 (in Japanese with English abstract).
Sakai, S., T. Iidaka, and Group for the aftershock observations of the 2007 Noto Hanto Earthquake, Aftershock observation of the Noto Hanto Earthquake in 2007 by temporary seismic observations, Abstract for Japan Geoscience Union Joint Meet., Z255-P050, 2007.
Smith, W. H. F. and D. T. Sandwell, Global Seafloor Topography from Satellite Altimetry and Ship Depth Soundings, Science, 277, 1957–1962, 1997.
The Gravity Research Group in Southwest Japan, Gravity Measuremnts and Database in Southwest Japan, Gravity Database of Southwest Japan (CD-ROM), Bull. Nagoya University Museum, Special Rep., No. 9, 2001.
Wessel, P. and W. H. F. Smith, New, improved version of the Generic Mapping Tools released, EOS Trans. AGU, 79, 579, 1998.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made.
The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.
To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/.
About this article
Cite this article
Honda, R., Hiramatsu, Y., Kono, Y. et al. Gravity anomalies and the geologic block structures in and around the aftershock area of the 2007 Noto Hanto Earthquake. Earth Planet Sp 60, 111–115 (2008). https://doi.org/10.1186/BF03352770
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1186/BF03352770
Key words
- Gravity anomaly
- the 2007 Noto Hanto Earthquake
- geologic block structure