scholarly journals Study of blind thrust faults underlying Tokyo and Osaka urban areas using a combination of high-resolution seismic reflection profiling and continuous coring

2009 ◽  
Vol 46 (5) ◽  
Author(s):  
Y. Sugiyama ◽  
K. Mizuno ◽  
F. Nanayama ◽  
T. Sugai ◽  
H. Yokota ◽  
...  
Keyword(s):  
High Resolution ◽  
Urban Areas ◽  
Seismic Reflection ◽  
Thrust Faults ◽  
Blind Thrust ◽  
Seismic Reflection Profiling

Identifying seismically active blind thrusts by geomorphology and seismic reflection profiles in a reactivated back-arc failed rift basin, Northeast Japan

2020 ◽  
Author(s):  
Tatsuya Ishiyama ◽  
Hiroshi Sato ◽  
Naoko Kato ◽  
Susumu Abe ◽  
Satoru Yokoi ◽  
...  
Keyword(s):  
High Resolution ◽  
Seismic Reflection ◽  
Data Depth ◽  
Alluvial Plain ◽  
The Sea Of Japan ◽  
Seismic Reflection Data ◽  
Reflection Data ◽  
Blind Thrust ◽  
Structural Growth ◽  
Back Arc

<p>Back-arc failed rifts in many subduction zones are recognized as mechanically and thermally weak zones that possibly play important roles in strain accommodation at later post-rift stages within the overriding plates. In case of Miocene back-arc failed rift structures in the Sea of Japan in the Eurasian-Pacific subduction system, Quaternary activity of post-rift positive inversion of normal faults are predominant, part of which are blurred by fast subsidence in alluvial plains above densified lower crust associated with mafic intrusion into rift axis. To define such active fault-related structures in alluvial plain with subtle geomorphic signatures, we collected new high-resolution seismic reflection data across the alluvial plain (Shonai plain) in Northeast Japan, where an enigmatic 1894 earthquake event (M7.0) caused devastating damages on local communities. We deployed hundreds of portable offline seismic recorders covering whole seismic lines and provided seismic shots using Vibroseis trucks at all nearby receivers, to create high-resolution, depth-converted cross sections based on seismic reflection data. Depth-converted sections to 2-3 km depth clearly illuminate pairs of west-vergent, thrust-related folds that deformed Miocene to Pleistocene sedimentary and volcaniclastic rocks. Among them, we defined previously unrecognized, west-dipping blind thrust structures beneath coastal plains that deform Pleistocene and Holocene basin-fill units. Structures of these blind thrusts are consistent with distribution of earthquake-damaged houses and, at least partly, might activate during the 1894 seismic event. Interestingly, upward extension of synclinal axial surfaces are consistent with very subtle west-facing fold scarps that deform alluvial plain deposits illuminated by DEM, suggesting recent fault activities and related structural growth of thrust-related folds. These examples nicely demonstrate that combining subtle geomorphology of constrained by DEM and high resolution seismic reflection profiling is an effective tool to define recent structural growth and activity of otherwise inaccessible blind thrust structures and mitigating their elusive seismic hazards.</p>

High Resolution Seismic Reflection Profiling At Aberdeen Proving Grounds, Maryland

1996 ◽  
Author(s):  
Richard D. Miller ◽  
Jianghai Xia ◽  
Stanley Swartzel ◽  
Jose Llopis ◽  
Paul Miller
Keyword(s):  
High Resolution ◽  
Seismic Reflection ◽  
Seismic Reflection Profiling

High Resolution Seismic Reflection Profiling at Aberdeen Proving Grounds, Maryland

1996 ◽  
Author(s):  
Richard D. Miller ◽  
Jianghai Xia ◽  
Stanley Swartzel ◽  
Jose Llopis ◽  
Paul Miller
Keyword(s):  
High Resolution ◽  
Seismic Reflection ◽  
Seismic Reflection Profiling

High-resolution seismic reflection profiling of the active fold-and-thrust systems in the Shonai backarc basin, northern Honshu, Japan

2020 ◽  
Author(s):  
Naoko Kato ◽  
Hiroshi Sato ◽  
Tatsuya Ishiyama
Keyword(s):  
High Resolution ◽  
Seismic Reflection ◽  
Active Fault ◽  
Fault System ◽  
The Sea Of Japan ◽  
Thrust Belt ◽  
Backarc Basin ◽  
Fold And Thrust Belt ◽  
Seismogenic Source ◽  
Seismic Reflection Profiling

<p>Northern Honshu, Japan, forms a classical example of the trench-arc-backarc basin system. Along the coast of the Sea of Japan, Miocene aborted rifts were developed filled with thick Neogene sediments and form an active fold-and-thrust belt. Devastative crustal earthquakes, such as the Shonai earthquake 1894 (M7), occurs historically. To reveal the relationship between active fault and fold structure with seismogenic source faults is significant for the evaluation of seismic hazards and possible risk. In the Shonai plain, northern Honshu, we performed 2D high-resolution seismic reflection profiling across the active faults. Seismic data was collected by 10 m shot and receiver interval using Enviro vib and Minivib (IVI) to obtain high-resolution image. Along some of the seismic lines, seismic reflection survey was recorded by fixed 800-1000 channels, producing high number of folds. The resultant seismic profiles provide the image of a fold-and-thrust belt developed in the Miocene volcanic rift basin. Former syn-rift faults reactivated as reverse faults and thin-skinned deformation prevails in the post rift sediments forming detachment in the Miocene over pressured mudstone units. Fault-related folds and wedge thrusting is common feature of the shortening deformation. There are two active thrust systems in the Shonai basin. One is known active fault system along the eastern margin of the Shonai plain and the other is an active-blind - thrust located in the central part of the basin. The late Quaternary tectonic movements along this fault was confirmed by the high-resolution seismic profiling. </p>

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