Seismic velocity structure below the island of Hawaii from local earthquake data
Seismic velocity structure below the island of Hawaii from local earthquake data
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根据当地地震数据得出的夏威夷岛下方的地震速度结构
DOI：
10.1029/jb084ib05p02331
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发表时间：
1979
影响因子：
--
通讯作者：
R. Koyanagi
中科院分区：
文献类型：
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作者：
R. Crosson;R. Koyanagi
同时反演了夏威夷37个台站网络记录的45次地震和3次爆炸的P波到达时间数据的震源参数、作为深度函数的纵波速度和台站校正。震源深度范围从近地表到约35公里，大多数事件发生在基拉韦厄火山附近。所得到的构造模型在地壳底部有一个明显的、约束良好的低速带。这个特征最容易解释为一个蛇形过渡层，尽管很难完全排除热起源。M不连续面上地幔速度约为8.3 km/s，速度梯度随深度增加约为0.01 km/s/km。有证据表明，岛下有一个凹陷的地壳，可能是对火山负荷的反应。台站改正与区域布格重力变化呈负相关。特别是莫纳罗亚火山的山顶，与侧翼站相比，到达时间早了0.5秒，这表明火山中的高速核心几乎延伸到火山堆的底部。
P wave arrival time data from 45 earthquakes and three explosions recorded on the 37-station Hawaii network were inverted simultaneously for hypocenter parameters, compressional wave velocity as a function of depth, and station corrections. Hypocenter depths range from near surface to approximately 35 km, with most events near Kilauea volcano. The structure model obtained has a distinct and well-constrained low-velocity zone at the base of the crust. This feature is most readily explained as a serpentinized transition layer, although it is difficult to completely rule out a thermal origin. Upper mantle velocity at the M discontinutiy is about 8.3 km/s with a gradient estimated to be about a 0.01-km/s/km increase in velocity with depth. Evidence is found for a crust which is depressed beneath the island, presumably in response to the volcanic load. Station corrections exhibit an inverse correlation with regional Bouguer gravity variations. The summit of Mauna Loa volcano in particular has arrival times anomalously early by as much as 0.5 s compared to flank stations, indicating that a high-velocity core in the volcano extends nearly to the base of the volcanic pile.