顾国华, 王武星. GPS测得的2018年夏威夷6.9级地震与火山喷发地壳运动[J]. 武汉大学学报 ( 信息科学版), 2019, 44(8): 1191-1197, 1204. DOI: 10.13203/j.whugis20180463
引用本文: 顾国华, 王武星. GPS测得的2018年夏威夷6.9级地震与火山喷发地壳运动[J]. 武汉大学学报 ( 信息科学版), 2019, 44(8): 1191-1197, 1204. DOI: 10.13203/j.whugis20180463
GU Guohua, WANG Wuxing. Crustal Motions Observed from GPS Observations for the M6.9 Earthquake in Hawaii and the Eruption of the Kilauea Volcano in 2018[J]. Geomatics and Information Science of Wuhan University, 2019, 44(8): 1191-1197, 1204. DOI: 10.13203/j.whugis20180463
Citation: GU Guohua, WANG Wuxing. Crustal Motions Observed from GPS Observations for the M6.9 Earthquake in Hawaii and the Eruption of the Kilauea Volcano in 2018[J]. Geomatics and Information Science of Wuhan University, 2019, 44(8): 1191-1197, 1204. DOI: 10.13203/j.whugis20180463

GPS测得的2018年夏威夷6.9级地震与火山喷发地壳运动

Crustal Motions Observed from GPS Observations for the M6.9 Earthquake in Hawaii and the Eruption of the Kilauea Volcano in 2018

  • 摘要: 2018-05-05美国夏威夷发生基拉韦厄火山喷发和6.9级地震,直接利用Nevada Geodetic Laboratory(http://geodesy.unr.edu)的全球定位系统连续观测站NA12数据处理结果,得到夏威夷地区的地壳运动趋势,与采用区域参考框架处理方法所得结果一致。本次6.9级地震前的形变主要为地震形变前兆,其次为火山喷发活动的影响;同震位移是地震断层破裂的结果;而震后邻近火山小范围内位移量大。地震前近震中垂直位移无积累。同震水平位移方向和震前积累水平位移的总方向相反,同震水平位移为震前积累的水平位移弹性回跳,由此证明,震前积累的水平位移是地震前兆。同其他大地震相比,夏威夷地震前震中区小范围介质也接近于弹性。近震中临震地壳运动非常显著,是震前断层的预滑或预位移。观测得到的临震形变前兆特殊震例可为探索短临形变前兆提供新线索。地震前夏威夷岛受北西向水平地壳运动挤压,导致地震断层倾滑剪切破裂,产生地震,符合提出的回跳或弹性回跳模型,或称为压-剪回跳或弹性回跳模型。

     

    Abstract: In 2018 the Kilauea volcano erupted and on May 5, an earthquake of M6.9 occurred in Hawaii. Though the methods used by the authors to get the results in the regional reference frame and the methods for NA12 results are different in some way, both results for NA12 are in good agreement. The results in NA12 at GPS continuous observation stations, directly obtained from http://geodesy.unr.edu, were analyzed to show crustal motions in Hawaii. The preseismic crustal movements were dominated by deformation precursory to the earthquake while the influence of the volcanic eruption was secondary. The coseismic displacements were the result of the rupture of the earthquake fault. The post seismic displacements around the crater were quite large but localized in a rather small area. No accumulated preseismic vertical displacements were observed near the epicenter. The coseismic horizontal displacements were instant and dramatic displacements in opposite sense to the accumulated preseismic horizontal displacements so they were elastic rebound of the accumulated preseismic horizontal displacements. Therefore, the accumulated preseismic horizontal displacements were precursors to the earthquake. In comparison to other large earthquakes, the media of a quite small area around the epicenter was nearly elastic. The crustal movements near the epicenter, imminent to the earthquake were quite significant. They showed the preslip of the earthquake fault or preseismic displacements. This earthquake is a special case that showed the existence of imminent deformation precursory to the earthquake. They are new clues for the future observations and study on the imminent precursors. The M6.9 earthquake in Hawaii was the result of compression of the crust of the island by horizontal motion in NW direction before the earthquake, which led to shear rupture of the earthquake fault that caused the earthquake. This fact is in good agreement with the model of rebound or elastic rebound proposed by the authors, the compression-shear model of rebound or elastic rebound, that is, the model of preseismic compression that leads to shear rupture of the earthquake.

     

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