Shallow velocity structure of Stromboli volcano, Italy, derived from small-aperture array measurements of Strombolian tremor
Shallow velocity structure of Stromboli volcano, Italy, derived from small-aperture array measurements of Strombolian tremor
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意大利斯特龙博利火山的浅层速度结构，源自斯特龙博利震颤的小孔径阵列测量
DOI：
10.1785/bssa0880030653
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发表时间：
1998
影响因子：
3
通讯作者：
R. Scarpa
中科院分区：
文献类型：
--
作者：
B. Chouet;G. Luca;G. Milana;P. Dawson;M. Martini;R. Scarpa
利用部署在斯特龙博利火山北侧的短周期地震仪的小孔径阵列数据，分析了斯特龙博利火山的震动波场特性。地震仪采用半径为60米和150米的两个半圆阵和长度为600米的线性阵。数据分析采用了一种时空相关技术，该技术专门用于研究由火山活动和分布在岛上的散射源产生的瑞利波和洛夫波的平稳随机波场。作为运动三个分量的频率函数而导出的相关系数清楚地定义了瑞利波和洛夫波的频散特性。洛夫波和瑞利波分别贡献了70%和30%的表面波功率。瑞利波的相速度在2hz时为1000m /s ~ 9hz时为350m /s，洛夫波的相速度在800 ~ 400m /s之间。这些速度与夏威夷基拉韦厄火山东部裂谷Puu Oo附近测量到的速度相似，尽管斯特隆博利瑞利波的频散特性显示出对频率的更强依赖性。如此低的速度与密集裂缝固化玄武岩的预期值一致。假设这些色散代表瑞利波和洛夫波的基本模式，那么阵列下面的速度模型的色散曲线是颠倒的。
The properties of the tremor wave field at Stromboli are analyzed using data from small-aperture arrays of short-period seismometers deployed on the north flank of the volcano. The seismometers are configured in two semi-circular arrays with radii of 60 and 150 m and a linear array with length of 600 m. The data are analyzed using a spatiotemporal correlation technique specifically designed for the study of the stationary stochastic wave field of Rayleigh and Love waves generated by volcanic activity and by scattering sources distributed within the island. The correlation coefficients derived as a function of frequency for the three components of motion clearly define the dispersion characteristics for both Rayleigh and Love waves. Love and Rayleigh waves contribute 70% and 30%, respectively, of the surface-wave power. The phase velocities of Rayleigh waves range from 1000 m/sec at 2 Hz to 350 m/sec at 9 Hz, and those for Love waves range from 800 to 400 m/sec over the same frequency band. These velocities are similar to those measured near Puu Oo on the east rift of Kilauea Volcano, Hawaii, although the dispersion characteristics of Rayleigh waves at Stromboli show a stronger dependence on frequency. Such low velocities are consistent with values expected for densely cracked solidified basalt. The dispersion curves are inverted for a velocity model beneath the arrays, assuming those dispersions represent the fundamental modes of Rayleigh and Love waves.