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与海底火山相关的最大灾害之一不在于火山本身,而在于潜在的火山侧翼的塌陷(McGuire,1996;Moore,et al,1989)。这种侧翼塌陷可以酿成毁灭性的海啸,不仅会波及邻近地区,而且对整个大洋盆地沿岸城市都会造成巨大威胁(Ward,2001)。位于美国夏威夷岛的基拉韦厄火山是一座具有潜在侧翼塌陷危险的火山(Ward,2001;Lipman,et al,1988),因此该火山一直被大地测量台网密切监测,该台网包括全球定位系统(GPS)的接收仪、倾斜仪和应变仪。我们发现,2000年11月上旬,该台网记录到短瞬的东南向位移,我们将其解释为发生了一次无震断层滑动。这一滑动持续了约36 h,等同于一次矩震级为5.7的地震,并且最大滑动速度为6 cm/d。对 GPS 数据的反演表明,4.5 km 深处存在一个小倾角逆冲断层,我们将它解释为希利纳巴利-霍莱伊巴利正断层系的下倾部分。这表明连续记录的大地测量台网可以监测到加速滑动,也许可以对火山侧翼塌陷作出预警。
One of the biggest disasters associated with submarine volcanoes is not the volcano itself but the potential volcanic flanking collapse (McGuire, 1996; Moore, et al., 1989). This flank collapse can lead to a devastating tsunami that not only affects neighboring areas but also poses a tremendous threat to coastal cities throughout the ocean basin (Ward 2001). The Kilauea volcano on Hawaii Island in the United States is a volcano with potential flank collapse (Ward, 2001; Lipman, et al., 1988) and is therefore closely monitored by the Geodetic Survey Network, which includes Global Positioning System (GPS) receiver, inclinometer and strain gauge. We found that in early November 2000, the station recorded short-term, southeastward displacements, which we interpreted as a seismic fault slip. This sliding lasted about 36 h, equivalent to an earthquake of moment magnitude 5.7, with a maximum sliding speed of 6 cm / d. The inversion of the GPS data shows that there is a small dip thrust at depth 4.5 km, which we interpret as the downtilt part of the Helinapali-Horai-Ibali normal fault system. This indicates that the continuously recorded geodetic network can detect accelerated slippage and may be able to warn the flanking collapse of the volcano.