Complex rupture mechanism and topography control symmetry of mass-wasting pattern, 2010 Haiti earthquake

详细信息    查看全文

• 作者：Tolga Gorum^a ; ^b ; ^gorum@itc.nl ; Cees J. van Westen^a ; Oliver Korup^c ; Mark van der Meijde^a ; Xuanmei Fan^a ; ^d ; Freek D. van der Meer^a
• 关键词：Landslide ; Earthquake ; Thrust fault ; Fault rupture dynamics ; Topography ; Haiti
• 刊名：Geomorphology
• 出版年：2013
• 出版时间：15 February, 2013
• 年：2013
• 卷：184
• 期：Complete
• 页码：127-138
• 全文大小：4181 K

文摘

The 12 January 2010 M_w 7.0 Haiti earthquake occurred in a complex deformation zone at the boundary between the North American and Caribbean plates. Combined geodetic, geological and seismological data posited that surface deformation was driven by rupture on the L¨¦ogane blind thrust fault, while part of the rupture occurred as deep lateral slip on the Enriquillo-Plantain Garden Fault (EPGF). The earthquake triggered > 4490 landslides, mainly shallow, disrupted rock falls, debris-soil falls and slides, and a few lateral spreads, over an area of ~ 2150 km². The regional distribution of these slope failures defies those of most similar earthquake-triggered landslide episodes reported previously. Most of the coseismic landslides did not proliferate in the hanging wall of the main rupture, but clustered instead at the junction of the blind L¨¦ogane and EPGF ruptures, where topographic relief and hillslope steepness are above average. Also, low-relief areas subjected to high coseismic uplift were prone to lesser hanging wall slope instability than previous studies would suggest. We argue that a combined effect of complex rupture dynamics and topography primarily control this previously rarely documented landslide pattern. Compared to recent thrust fault-earthquakes of similar magnitudes elsewhere, we conclude that lower static stress drop, mean fault displacement, and blind ruptures of the 2010 Haiti earthquake resulted in fewer, smaller, and more symmetrically distributed landslides than previous studies would suggest. Our findings caution against overly relying on across-the-board models of slope stability response to seismic ground shaking.