意大利诺尔恰Ms6.2级地震震害异常原因分析

当地时间2016年8月24日凌晨3时36分,意大利中部拉齐奥大区列蒂省诺尔恰镇发生里氏6.2级地震。此次地震震级不大,但一些古镇震害极其严重,出现多个烈度异常区块。通过对此次地震异常区建筑结构、地质结构及地形特征解剖,运用几年来的斜坡地震动响应规律监测成果,采用数值模拟分析,揭示了震级不大、距震中较远的条件下,地形放大效应同样可造成极其严重的震害。中世纪修建并保留至今的古建筑,大多为砖木结构,整体性较差,抗震性较弱,且由于历史原因多修建在孤立突出的山头上,在地形放大作用下造成了极其严重的伤亡。

Causes of Abnormal Damage of Ms6.2 Earthquake in Norcia,Italy

At local time 3:36 on August 24, 2016, an M_s6.2 earthquake hit the town of Norcia in Lazio Rieti Province of central Italy. Despite that the earthquake magnitude was not big, some ancient towns were severely damaged. In this paper we revealed the causes of the abnormal damage by analyzing the architectural structure, geological structure, and topographic features in the study area according to monitoring achievements of seismic response of slopes in recent years in association with numerical simulation. Results uncover that terrain amplification effect could give rise to severe seismic disaster in spite of small magnitude and long distance to the epicenter. The poor seismic performance of aged buildings, the shallow seismic focus, the amplification effect of seismic wave induced by isolated topography are key factors resulting in the large number of casualties.