Low-frequency and broad-band source models for the 2009 L'Aquila, Italy, earthquake
Low-frequency and broad-band source models for the 2009 L'Aquila, Italy, earthquake
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2009 年意大利拉奎拉地震的低频和宽带震源模型
DOI：
10.1111/j.1365-246x.2012.05602.x
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
and Hiroe Miyake
中科院分区：
文献类型：
--
作者：
Natalia Poiata;Kazuki Koketsu,Alessandro Vuan;and Hiroe Miyake
2009年意大利拉奎拉地震（Mw6.3）产生了一次正常断层事件中前所未有的地震记录，因此代表了在人口密集地区发生破坏性中震级地震的重要案例研究。通过对远震和强震资料的分析，研究了2009年拉奎拉地震的低频和宽带震源过程。通过对远震和近场强震数据的波形反演，确定了一个低频（<0.5 Hz）震源模型，得到了一个位于震源东南约8公里处的主要陡坡的滑动分布。利用经验格林函数方法估计了位于安娜村以下震源东南约42 km2的强震发生区域的宽带（0.2 ~ 10 Hz）震源特征。这与反演分析中陡坡的位置一致，说明地震中产生的低频和宽带地面运动产生于断面上相似的位置。强震发生区的位置与INGV报道的大震观测烈度分布也有很好的相关性。据报道，IX-X的最大大震烈度位于震中东南部，在Onna测得烈度为X。2009年拉奎拉主震的震源性质表明，强震产生区的估计大小与利用内陆地壳地震经验震源标度关系所作的预测一致，表明应力降约为10 MPa。这进一步表明，2009年拉奎拉地震的应力下降与之前在亚平宁山脉中部和南部记录的地震相似。
The 2009 L'Aquila, Italy, earthquake (Mw6.3) produced an unprecedented number of seismological records for a normal faulting event, and hence represents an important case study of damaging moderate magnitude earthquakes occurring in densely inhabited areas. We have investigated the source process of the 2009 L'Aquila earthquake in both the low- and broad-band frequency ranges by analysing the teleseismic and strong motion data. A low-frequency (<0.5 Hz) source model has been determined by waveform inversion of teleseismic and near-field strong motion data, yielding slip distributions with a major asperity located about 8 km southeast of the hypocentre. The broad-band (0.2–10 Hz) source characteristics were estimated using the empirical Green's function method providing the strong motion generation area of about 42 km2located southeast of the hypocentre below the village of Onna. This coincides with the location of the asperity from the inversion analysis, indicating that the low-frequency and broad-band ground motions produced during the earthquake were generated at similar locations on the fault plane. The position of the strong motion generation area also correlates well with the distribution of observed macroseismic (MCS) intensities reported by INGV. The maximum macroseismic intensities of IX–X were reported southeast of the epicentre, with an intensity of X measured in Onna. The source properties of the 2009 L'Aquila mainshock reveal the estimated size of the strong motion generation area to be in agreement with predictions made using empirical source scaling relation for inland crustal earthquakes, implying a stress drop of approximately 10 MPa. This further indicates that the 2009 L'Aquila earthquake involved a stress drop similar to that of previously recorded earthquakes in the Central and Southern Apennines.