Details

Autor(en) / Beteiligte

• Abe, Shintaro
• Aoyagi, Yasuhira

Titel

Influence of Plate Subduction and Trench Type Great Earthquakes on Crustal Deformation

Ist Teil von

• Eos (Washington, D.C.), 2006-09, Vol.87

Erscheinungsjahr

2006

Quelle

EZB Free E-Journals

Beschreibungen/Notizen

• When we build an important institution related to atomic energy such as a nuclear power plant or a high level waste disposal institution, it is desirable that crustal deformation in the neighboring area is stable. Stability of the crustal deformation have means for the crust not to display sedimentation and upheaval by volcano and fault or plate movement. The future of crustal deformation of the Japanese Archipelago is predicted based on the premise that 'the present crustal deformation continues in the future unless the present conditions .of plate movement change.' Future crust struc ture is predicted by extending inclination from the past to the present to the future if based on this premise. The technique that is needed to grasp inclination of crustal deformation from the past to the present is already well established as an earth science investigation technique. Establishment of quantitative crustal deformation analysis technique based on this investigation technique and the prediction concept mentioned above is desired. To examine the influence that plate subuduction gives to the Japanese Archipelago by numerical value simulation from the point of view of accumulation of stress. Furthermore, to estimate crustal deformation when a trench type great earthquake occurs. And to clarify long-term crustal deformation when this earthquake is repeated. (1)Crustal deformation with regular plate subuduction. At first we supposed main tectonic line and geological boundary distributed over the Japanese Archipelago to be the area where hardness was low. And, based on this supposition, a crustal structure model was made. We calculated crustal deformation with regular plate subduction for this model by the finite element method. As a result, some areas where stress was concentrated were recognized. These areas are almost equal to the area where meters above the sea level geographically. In other words it is thought that these areas were formed by a structural geology factor with influence of regular plate subduction. (2)Crustal deformation caused in connection with a trench type great earthquake. Crustal deformation caused in connection with a great earthquake which occurs in a plate subuduction area was calculated by finite element method. Consequently, in the calculation when the trench type earthquake of M8 class occurs in offshore Tokachi, offshore Sanriku, offshore Shikoku and Hyuganada, the upheaval region appeared on the earthquake source fault, and the subsidence region spread to the land side. Especially, in offshore Shikoku, the upheaval region spread to the tip part of the Cape Muroto and Kii Peninsula. (3)Crustal deformation when regular plate subuduction and a trench type great earthquake are repeated. In the calculation when the subduction due to earthquake source fault continued for 100 years, the subsidence region spread in all areas. In offshore Shikoku, the upheaval reaches land by calculation when subduction for 100 years and a trench type great earthquake are repeated. In other areas, although the seabed on earthquake source fault upheaves, the upheaval does not reach to the land.