Shallow earthquake inhibits unrest near Chiles-Cerro Negro volcanoes, Ecuador-Colombian border
Shallow earthquake inhibits unrest near Chiles-Cerro Negro volcanoes, Ecuador-Colombian border
复制标题
DOI：
10.1016/j.epsl.2016.06.046
复制
发表时间：
2016-09-15
影响因子：
5.3
通讯作者：
Samsonov, Sergey V.
中科院分区：
文献类型：
--
作者：
Ebmeier, Susanna K.;Elliott, John R.;Samsonov, Sergey V.
岩浆运动或水库增压可以驱动成群的低震级火山构造地震，以及局部构造断层上偶尔发生的较大地震（>M5）。火山附近的>M5地震很难解释火山灾害的演变，但通常与火山爆发有关，在某些情况下会增强岩浆的上升。我们目前的大地测量观测，从第一集的动荡发生在智利和塞罗内格罗德马亚斯克尔火山附近的厄瓜多尔-哥伦比亚边境。2014年10月，一群火山构造地震活动在火山以南的M-w 5.6地震中达到高潮。这次地震的卫星雷达数据检测到的位移与1886年最后一次破裂的SSW-NNE向断层带内1.4-3.4公里深处逆断层上的右旋斜滑一致。全球定位系统台站的测量记录了地震前20天的隆起，可能源自智利火山以南10-15公里处的一个压力源，深度超过13公里。在Mw5.6地震后，隆起停止，地震活动率开始下降。这种活动下降的潜在机制包括岩浆进入地壳浅层的运动速度下降，这可能是由于流体通道的限制。我们的观察表明，火山动荡期间触发的地震可以抑制岩浆过程，并对地震和火山之间的相互作用的危害解释的影响。(C)2016爱思唯尔B. V.保留所有权利。
Magma movement or reservoir pressurisation can drive swarms of low-magnitude volcano-tectonic earthquakes, as well as occasional larger earthquakes (>M5) on local tectonic faults. Earthquakes >M5 near volcanoes are challenging to interpret in terms of evolving volcanic hazard, but are often associated with eruptions, and in some cases enhance the ascent of magma. We present geodetic observations from the first episode of unrest known to have occurred near Chiles and Cerro Negro de Mayasquer volcanoes on the Ecuador-Colombian border. A swarm of volcano-tectonic seismicity in October 2014 culminated in a M-w 5.6 earthquake south of the volcanoes. Satellite radar data spanning this earthquake detect displacements that are consistent with dextral oblique slip on a reverse fault at depths of 1.4-3.4 km within a SSW-NNE trending fault zone that last ruptured in 1886. GPS station measurements capture 20 days of uplift before the earthquake, probably originating from a pressure source similar to 10-15 km south of Volcan Chiles, at depths exceeding 13 km. After the Mw 5.6 earthquake, uplift ceased and the rate of seismicity began to decrease. Potential mechanisms for this decline in activity include a decrease in the rate of movement of magma into the shallow crust, possibly caused by the restriction of fluid pathways. Our observations demonstrate that an earthquake triggered during volcanic unrest can inhibit magmatic processes, and have implications for the hazard interpretation of the interactions between earthquakes and volcanoes. (C) 2016 Elsevier B.V. All rights reserved.