Seismoacoustic Coupled Signals From Earthquakes in Central Italy: Epicentral and Secondary Sources of Infrasound
Seismoacoustic Coupled Signals From Earthquakes in Central Italy: Epicentral and Secondary Sources of Infrasound
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DOI：
10.1002/2017gl076125
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发表时间：
2018-01
影响因子：
5.2
通讯作者：
S. Shani-Kadmiel;J. Assink;P. Smets;L. Evers
中科院分区：
文献类型：
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作者：
S. Shani-Kadmiel;J. Assink;P. Smets;L. Evers
在这项研究中，我们分析了意大利中部三场地震的次声信号。兆瓦 6.0 阿马特里切、兆瓦 5.9 维索和兆瓦 6.5 诺尔恰地震产生了显着的震中地面运动，与大气耦合并产生次声波。 I26DE 检测到震中地震和次声波信号；然而，还检测到在地震波列之后、震中次声信号之前到达的第三种类型的信号。这种特殊的信号以声波速度在阵列中传播，但与之相关的速度是声速的 3 倍。使用欧洲中期天气预报中心的大气条件进行的与大气无关的反投影和全 3D 射线追踪被用来证明这种快速到达的次声信号源自距震中 400 多公里的地面运动。二次次声波片的位置与光线追踪反投影所描绘的最接近 I26DE 的反弹点一致。
In this study we analyze infrasound signals from three earthquakes in central Italy. The Mw 6.0 Amatrice, Mw 5.9 Visso, and Mw 6.5 Norcia earthquakes generated significant epicentral ground motions that couple to the atmosphere and produce infrasonic waves. Epicentral seismic and infrasonic signals are detected at I26DE; however, a third type of signal, which arrives after the seismic wave train and before the epicentral infrasound signal, is also detected. This peculiar signal propagates across the array at acoustic wave speeds, but the celerity associated with it is 3 times the speed of sound. Atmosphere‐independent backprojections and full 3‐D ray tracing using atmospheric conditions of the European Centre for Medium‐Range Weather Forecasts are used to demonstrate that this apparently fast‐arriving infrasound signal originates from ground motions more than 400 km away from the epicenter. The location of the secondary infrasound patch coincides with the closest bounce point to I26DE as depicted by ray tracing backprojections.