Source location of long period seismicity at Volcàn de Colima, México
Source location of long period seismicity at Volcàn de Colima, México
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墨西哥科利马火山长周期地震活动的震源位置
DOI：
10.1007/s00445-011-0447-2
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发表时间：
2011
影响因子：
3.5
通讯作者：
E. Pezzo
中科院分区：
文献类型：
--
作者：
S. Petrosino;P. Cusano;M. Rocca;D. Galluzzo;Justo Orozco;M. Bretón;J. Ibáñez;E. Pezzo
本文分析了2005年11月至2006年4月期间科利马火山(México)火山活动的地震活动，这些地震活动是由火山喷发研究所(INGV)、科利马大学火山观测所和格拉纳达大学Andaluz de Geofisica研究所在实地考察期间记录的。根据火山地震的频谱特征，已识别出三种不同类型的火山地震：A型(0.3-1 GHz)、B型(1-5 GHz)和C型(3-4 GHz)。对A类事件的偏振分析结果表明，径向运动占主导地位，波场由纵波(P)和在垂直面(SV)极化的横波组成，而信号总是以负极性开始。A型、B型和C型地震已经使用包括地形在内的平面分层模型和3D模型进行了定位。震中分布表明，A型信号的来源非常浅，仅限于陨石坑下方约1公里处的一个小体积。相比之下，B型和C型地震的震源要深得多，大多数震源位于体积约为1千米的中心，中心深度为2.5-3千米。对A类地震进行了基于同一台站记录的不同事件波形之间互相关性的聚类分析。只发现了两个震群，其中只包括一小部分事件，这表明在我们的调查期间，地震家庭并不常见。
This paper presents an analysis of seismicity associated with the volcanic activity of Volcàn de Colima (México) and recorded in the period November 2005–April 2006 during a field survey by the Istituto Nazionale di Geofisica e Vulcanologia (INGV)–Osservatorio Vesuviano, the Observatorio Vulcanologico de Colima of Colima University and the Instituto Andaluz de Geofisica, University of Granada. Three different types of volcanic earthquakes have been identified on the basis of their spectral properties: Type A (0.3–1 Hz), Type B (1–5 Hz) and Type C (3–4 Hz). Results of polarization analysis applied to Type A events show a predominance of radial motion, indicating that the wavefield comprises compressional waves (P) and shear waves polarized in the vertical plane (SV), while the signal always begins with a negative polarity. Type A, B and C earthquakes have been located using both a flat layered model and a 3D model including topography. Hypocentre distributions indicate that the source of Type A signals is very shallow and confined to a small volume lying about 1 km below the crater. In contrast, the source of Type B and C events is significantly deeper, with most hypocentres located in a volume of about 1 km3 centred at 2.5–3 km depth. A cluster analysis based on the cross-correlation among the waveforms of different events recorded at the same station was applied to Type A earthquakes. Only two clusters, which include only a small percentage of events were found, indicating that earthquake families were uncommon during the period of our survey.