Field Detection of Microcracks to Define the Nucleation Stage of Earthquake Occurrence
Joint Authors
Takahashi, Kozo
Kobayashi, M.
Takamatsu, K.
Fujinawa, Yukio
Noda, Y.
Natsumeda, J.
Source
International Journal of Geophysics
Issue
Vol. 2013, Issue 2013 (31 Dec. 2013), pp.1-18, 18 p.
Publisher
Hindawi Publishing Corporation
Publication Date
2013-12-31
Country of Publication
Egypt
No. of Pages
18
Main Subjects
Abstract EN
Main shocks of natural earthquakes are known to be accompanied by preshocks which evolve following the modified Ohmori’s law in average over many samples.
Individual preshock activity, however, is far less systematic for predictive purposes.
On the other hand, the microcracks in laboratory rock experiments are always preceded to final rupture.
And, previous investigations of field acoustic emissions showed that the activity increases prominently before and after the main shock.
But there is no detection of any phenomena to identify the nucleation stage.
Here we show that a special underground electric field measurement could detect microcracks.
Pulse-like variations were classified into three groups (A, B, C) by frequency.
The B-type is suggested to define the nucleation period: activity increases sharply following the modified Omori’s law before the main shock and there is no activity afterward.
The B-type is subgrouped into three types possibly corresponding to crack-rupture modes.
The variations are supposed to be induced by crack occurrence through electrokinetic effects in the elastic-porous medium.
The detection distance is suggested to be several orders larger than that of the acoustic emission due to the effective smallness of dissipation rate, and the waveform can be used to infer the rupture mode.
American Psychological Association (APA)
Fujinawa, Yukio& Noda, Y.& Takahashi, Kozo& Kobayashi, M.& Takamatsu, K.& Natsumeda, J.. 2013. Field Detection of Microcracks to Define the Nucleation Stage of Earthquake Occurrence. International Journal of Geophysics،Vol. 2013, no. 2013, pp.1-18.
https://search.emarefa.net/detail/BIM-488357
Modern Language Association (MLA)
Fujinawa, Yukio…[et al.]. Field Detection of Microcracks to Define the Nucleation Stage of Earthquake Occurrence. International Journal of Geophysics No. 2013 (2013), pp.1-18.
https://search.emarefa.net/detail/BIM-488357
American Medical Association (AMA)
Fujinawa, Yukio& Noda, Y.& Takahashi, Kozo& Kobayashi, M.& Takamatsu, K.& Natsumeda, J.. Field Detection of Microcracks to Define the Nucleation Stage of Earthquake Occurrence. International Journal of Geophysics. 2013. Vol. 2013, no. 2013, pp.1-18.
https://search.emarefa.net/detail/BIM-488357
Data Type
Journal Articles
Language
English
Notes
Includes bibliographical references
Record ID
BIM-488357