scholarly journals Near‐field observations of an offshore M w 6.0 earthquake from an integrated seafloor and subseafloor monitoring network at the Nankai Trough, southwest Japan

2016 ◽  
Vol 121 (11) ◽  
pp. 8338-8351 ◽  
Author(s):  
L. M. Wallace ◽  
E. Araki ◽  
D. Saffer ◽  
X. Wang ◽  
A. Roesner ◽  
...  
Keyword(s):  
Nankai Trough ◽  
Near Field ◽  
Monitoring Network ◽  
Field Observations ◽  
Southwest Japan

scholarly journals Driving stress and seismotectonic implications of the 2013 Mw5.8 Awaji Island earthquake, southwestern Japan, based on earthquake focal mechanisms before and after the mainshock

2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Kazutoshi Imanishi ◽  
Makiko Ohtani ◽  
Takahiko Uchide
Keyword(s):  
Stress Field ◽  
Stress Tensor ◽  
Nankai Trough ◽  
Source Region ◽  
Local Scale ◽  
Southwest Japan ◽  
Stress Tensor Inversion ◽  
Earthquake Fault ◽  
Reverse Faulting ◽  
Before And After

Abstract A driving stress of the Mw5.8 reverse-faulting Awaji Island earthquake (2013), southwest Japan, was investigated using focal mechanism solutions of earthquakes before and after the mainshock. The seismic records from regional high-sensitivity seismic stations were used. Further, the stress tensor inversion method was applied to infer the stress fields in the source region. The results of the stress tensor inversion and the slip tendency analysis revealed that the stress field within the source region deviates from the surrounding area, in which the stress field locally contains a reverse-faulting component with ENE–WSW compression. This local fluctuation in the stress field is key to producing reverse-faulting earthquakes. The existing knowledge on regional-scale stress (tens to hundreds of km) cannot predict the occurrence of the Awaji Island earthquake, emphasizing the importance of estimating local-scale (< tens of km) stress information. It is possible that the local-scale stress heterogeneity has been formed by local tectonic movement, i.e., the formation of flexures in combination with recurring deep aseismic slips. The coseismic Coulomb stress change, induced by the disastrous 1995 Mw6.9 Kobe earthquake, increased along the fault plane of the Awaji Island earthquake; however, the postseismic stress change was negative. We concluded that the gradual stress build-up, due to the interseismic plate locking along the Nankai trough, overcame the postseismic stress reduction in a few years, pushing the Awaji Island earthquake fault over its failure threshold in 2013. The observation that the earthquake occurred in response to the interseismic plate locking has an important implication in terms of seismotectonics in southwest Japan, facilitating further research on the causal relationship between the inland earthquake activity and the Nankai trough earthquake. Furthermore, this study highlighted that the dataset before the mainshock may not have sufficient information to reflect the stress field in the source region due to the lack of earthquakes in that region. This is because the earthquake fault is generally locked prior to the mainshock. Further research is needed for estimating the stress field in the vicinity of an earthquake fault via seismicity before the mainshock alone.

scholarly journals Near-field observations of light confinement in a two dimensional lithium niobate photonic crystal cavity

2011 ◽  
Vol 110 (7) ◽  
pp. 074318 ◽  
Author(s):  
Jean Dahdah ◽  
Maria Pilar-Bernal ◽  
Nadège Courjal ◽  
Gwenn Ulliac ◽  
Fadi Baida
Keyword(s):  
Photonic Crystal ◽  
Lithium Niobate ◽  
Near Field ◽  
Field Observations ◽  
Two Dimensional ◽  
Photonic Crystal Cavity ◽  
Light Confinement

scholarly journals Interplate coupling along the Nankai Trough off southwest Japan derived from GPS measurements

1999 ◽  
Vol 26 (7) ◽  
pp. 927-930 ◽  
Author(s):  
Taku Ozawa ◽  
Takao Tabei ◽  
Shin-ichi Miyazaki
Keyword(s):  
Nankai Trough ◽  
Southwest Japan ◽  
Gps Measurements ◽  
Interplate Coupling

Nonlinear distortion of signals radiated by vibroseis sources

Geophysics ◽  
2004 ◽  
Vol 69 (4) ◽  
pp. 968-977 ◽  
Author(s):  
Andrey V. Lebedev ◽  
Igor A. Beresnev
Keyword(s):  
Thin Layer ◽  
Nonlinear Response ◽  
Nonlinear Distortion ◽  
Near Field ◽  
Quantitative Description ◽  
Harmonic Distortion ◽  
Seismic Energy ◽  
Field Observations ◽  
Contact Nonlinearity ◽  
The Difference

A model of nonlinearity of the contact between the vibrator baseplate and the ground is proposed to describe the distortion of vibroseis signals in the near‐field. A thin layer between the baseplate and the soil exhibits a strong nonlinear response because of the difference in its rigidity between the compression and tension phases. The model allows for a quantitative description of the transmission of seismic energy into the ground, including the observed harmonic distortion. However, the contact nonlinearity does not lead to the dependence of wave traveltimes on the amplitude of the force applied to the ground. This fact can be used in field observations to localize the source of the observed harmonic distortion.

Earthquake core inferred from near field observations

1985 ◽  
Vol 118 (3-4) ◽  
pp. 301-310 ◽  
Author(s):  
Yasuhiro Umeda
Keyword(s):  
Near Field ◽  
Field Observations
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