HARMONIC EXCITATION OF MANTLE RAYLEIGH-WAVES BY THE 1991 ERUPTION OF MOUNT PINATUBO, PHILIPPINES
HARMONIC EXCITATION OF MANTLE RAYLEIGH-WAVES BY THE 1991 ERUPTION OF MOUNT PINATUBO, PHILIPPINES
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DOI：
10.1029/92gl00258
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发表时间：
1992-04-03
影响因子：
5.2
通讯作者：
MORI, J
中科院分区：
文献类型：
--
作者：
KANAMORI, H;MORI, J
1991年6月15日菲律宾皮纳图博火山大喷发期间，世界上许多地震台记录到了周期约为230秒的异常长(至少两个小时)的地震波列。该波列在228秒和270秒处显示出两个尖锐的光谱峰值。该波列的群速度、相速度和质点运动表明它是瑞利波。最可能的激发机制是由火山持续热能通量引发的大气振荡的声波耦合。这两个光谱峰值对应于地球大气层声学和重力模式的特征周期。在0.003至0.01赫兹的频率范围内，相当于声耦合的垂直单力的大小为1.6x10(17)达因。结果表明，利用声学耦合瑞利波探测、表征和量化火山喷发是可能的。大气和固体地球的声耦合提供了一种独特的、持续时间较长的震源。
An unusually long (at least two hours) seismic wave train having periods of about 230 sec was recorded at many worldwide seismic stations during the major eruption of Mount Pinatubo in the Philippines on June 15, 1991. This wave train exhibits two sharp spectral peaks at 228 and 270 sec. The group velocity, phase velocity, and the particle motion of this wave train indicate that it is a Rayleigh wave. The most probable excitation mechanism is acoustic coupling of atmospheric oscillations that were set off by continuous thermal energy flux from the volcano. The two spectral peaks correspond to the characteristic periods of acoustic and gravity modes of the Earth's atmosphere. The magnitude of the vertical single force equivalent to the acoustic coupling is 1.6 x 10(17) dynes over a frequency band of 0.003 to 0.01 Hz. The results suggest the possibility of using acoustically coupled Rayleigh waves for detection, characterization and quantification of volcanic eruptions. Acoustic coupling of the atmosphere and the solid Earth provides a unique seismic source with long duration.