Research press release


Nature Geoscience

Complexities of the Haiti earthquake


G Hayesらは、地震学的観測、地質学的野外データおよび人工衛星測地学的測定を組み合わせて、地震の際に起きた地面の曲がりを解析した。表面の変形パターンをモデル化することで、どの断層が原因となったのかを評価することができた。彼らの結果は、地震が単一の断層の単純な破壊で起きたのではなく、複雑な一連の断層によって起きた可能性があることを示している。表面の変形パターンはこれまでに知られていないLeogane断層と名付けられた地下の逆断層の動きによって生じた。逆断層は年代の古い岩石を若い岩石の上に押し上げたが、地表を破壊することはなかった。

The devastating Haiti earthquake on 12 January 2010 involved slip on numerous faults, but resulted in very little deformation of the ground surface, according to a study published online this week in Nature Geoscience. Initially the Haiti earthquake was thought to be the consequence of movement along a single fault, which accommodates the motion between the Caribbean and North American plates. This paper is one of the first two to be published this month as part of Nature Geoscience’s special issue on the Haiti earthquake.

Gavin Hayes and colleagues used a combination of seismological observations, geologic field data and satellite geodetic measurements to analyse warping of the ground caused during the earthquake. By modelling the patterns of surface deformation, they were able to assess which fault was responsible. Their results showed that the earthquake may not have been caused by the simple rupture of a single fault, but instead may have involved a complex series of faults. The pattern of surface deformation was caused by some movement on a previously unknown, subsurface thrust fault, named the Leogane fault. The thrust fault caused older rocks to be pushed up over younger ones, but did not rupture the surface.

doi: 10.1038/ngeo977


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