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Open AccessStress field in northeastern Japan and its relationship with faults of recent earthquakes
Inversion tectonics, in which old normal faults act as reverse faults in current stress fields, are frequently observed in northeastern Japan (Tohoku District); however, the conditions that control these fault...
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Article
Open AccessFocal mechanisms and the stress field in the aftershock area of the 2018 Hokkaido Eastern Iburi earthquake (MJMA = 6.7)
The tectonic stress field was investigated in and around the aftershock area of the Hokkaido Eastern Iburi earthquake (MJMA = 6.7) occurred on 6 September 2018. We deployed 26 temporary seismic stations in the af...
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Open AccessErratum to: Preparatory and precursory processes leading up to the 2014 phreatic eruption of Mount Ontake, Japan
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Open AccessMonitoring eruption activity using temporal stress changes at Mount Ontake volcano
Volcanic activity is often accompanied by many small earthquakes. Earthquake focal mechanisms represent the fault orientation and slip direction, which are influenced by the stress field. Focal mechanisms of v...
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Article
Open AccessPreparatory process preceding the 2014 eruption of Mount Ontake volcano, Japan: insights from precise leveling measurements
Preparatory activity preceding the 2014 eruption of Mount Ontake volcano was estimated from vertical deformation detected using a precise leveling survey. Notable uplift (2006–2009) and subsidence (2009–2014) ...
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Open AccessSource mechanism of a VLP event immediately before the 2014 eruption of Mt. Ontake, Japan
The phreatic eruption of Mt. Ontake in 2014 was preceded for 25 s by a very long period (VLP) seismic event recorded at one broadband and three short-period seismic stations located within 5000 m of the summit...
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Open AccessPreparatory and precursory processes leading up to the 2014 phreatic eruption of Mount Ontake, Japan
We analyzed seismicity linked to the 2014 phreatic eruption of Mount Ontake, Japan, on 27 September 2014. We first relocated shallow volcano tectonic (VT) earthquakes and long-period (LP) events from August to...
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Open AccessTeleseismic inversion of the 2004 Sumatra-Andaman earthquake rupture process using complete Green’s functions
Spatial and temporal variations in coseismic slip distribution are often obtained by rupture process analyses using teleseismic body waves. Many analyses using teleseismic body waves were based on the ray theo...
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Open AccessPore pressure distribution in the focal region of the 2008 M7.2 Iwate-Miyagi Nairiku earthquake
The pore fluid pressure distribution in the focal region of the 2008 Iwate-Miyagi Nairiku earthquake was investigated through an analysis of the diversity of focal mechanisms. We inverted stress orientations a...
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Open AccessContinuous long-term array analysis of seismic records observed during the 2011 Shinmoedake eruption activity of Kirishima volcano, southwest Japan
We deployed a seismic array at a site 5 km east of Shinmoedake volcano, in the Kirishima volcanic complex of southwest Japan, five days after the sub-Plinian eruption on 26 January, 2011. The array record betw...
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Open AccessCorrelation between Coulomb stress changes imparted by large historical strike-slip earthquakes and current seismicity in Japan
To determine whether current seismicity continues to be affected by large historical earthquakes, we investigated the correlation between current seismicity in Japan and the static stress changes in the Coulom...
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Open AccessSource process for complex fault system of the 2007 Chuetsu-oki, Niigata, Japan, earthquake
The 2007 Chuetsu-oki earthquake occurred in the offshore area of Niigata Prefecture, central Japan, on 16 July 2007. The aftershock distribution shows two fault planes, dip** to the northwest and southeast, ...
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Open AccessShort-term spatiotemporal variations in the aftershock sequence of the 2004 mid-Niigata prefecture earthquake
We deployed 56 temporary seismic stations within approximately a month after the occurrence of the 2004 mid-Niigata prefecture earthquake. Using manually-picked arrival data obtained from the temporary and sur...
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Open AccessSimulation of strong ground motions caused by the 2004 off the Kii peninsula earthquakes
Strong ground motions caused by the Mj 7.4 2004 earthquake that occurred in the Nankai Trough to the southeast of the Kii Peninsula, Japan are simulated by a three-dimensional (3D) finite-difference method (FD...
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Source process of the recurrent Tokachi-oki earthquake on September 26, 2003, inferred from teleseismic body waves
On September 26, 2003, a large earthquake with a magnitude of 8.0 occurred along the Kuril trench off Tokachi, Hokkaido, Japan. We investigated the source process by using teleseismic P- and SH-wave data. The mai...
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The March 25, 1998 Antarctic Earthquake: Great earthquake caused by postglacial rebound
A large Mw = 8.1 earthquake occurred off southeast coast of Antarctica near the Balleny Island region on March 25, 1998. We inverted teleseismic body-wave records to determine the rupture pattern using an iterati...
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Source rupture process of the Papua New Guinea earthquake of July 17, 1998 inferred from teleseismic body waves
A large earthquake (Ms 7.1) occurred off northwest coast of Papua New Guinea (PNG), and a massive tsunami attacked villages to cause a devastating damage. In an attempt to ascertain the tsunami source, we investi...
