Rapid characterisation of large earthquakes by multiple seismic broadband arrays
Rapid characterisation of large earthquakes by multiple seismic broadband arrays
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DOI：
10.5194/nhess-10-923-2010
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发表时间：
2010-04
影响因子：
4.6
通讯作者：
D. Roessler;F. Krueger;M. Ohrnberger;L. Ehlert
中科院分区：
文献类型：
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作者：
D. Roessler;F. Krueger;M. Ohrnberger;L. Ehlert
抽象的。提出了一种自动程序来检索巽他岛弧俯冲带大地震的破裂参数。该方法基于标准阵列分析和震中距 30°–100° 范围内记录的宽带地震图。不需要对源机制进行假设。借助相似性，可以在单独的大孔径阵列上分析 P 波形的相干性。将波形迁移到10°×10°宽的震源区，以研究每个阵列的地震时空演化。每个阵列产生的相似源图的乘法提高了分辨率。事件开始后 25 分钟内获取并公布开始时间、持续时间、范围、方向和传播速度。 16 分钟内即可获得初步初步结果。他们的快速判断可能会改善地震和海啸灾害的缓解。实时应用程序将为 GITEWS 项目（德国印度尼西亚海啸预警系统）提供破裂参数。该方法适用于2007年9月12日的两次苏门答腊岛M8.0地震、2009年9月2日的爪哇岛M7.4地震以及2000年以来沿苏门答腊岛和爪哇岛发生的主要俯冲地震。对于震级为M≥8的最大地震，所获得的破裂参数最为稳健。结果表明，苏门答腊岛沿岸俯冲带的几乎整个孕震部分都发生了破裂。只有 2004 年的苏门答腊岛大地震和 2006 年 7 月 17 日的 M7.7 爪哇地震可以到达或接近海沟表面。除此之外，破裂显然仅限于 25 公里以下的深度。主要的地震间隙似乎仍然存在于巴东海岸和苏门答腊岛南端。
Abstract. An automatic procedure is presented to retrieve rupture parameters for large earthquakes along the Sunda arc subduction zone. The method is based on standard array analysis and broadband seismograms registered within 30°–100° epicentral distance. No assumptions on source mechanism are required. By means of semblance the coherency of P waveforms is analysed at separate large-aperture arrays. Waveforms are migrated to a 10°×10° wide source region to study the spatio-temporal evolution of earthquakes at each array. The multiplication of the semblance source maps resulting at each array increases resolution. Start, duration, extent, direction, and propagation velocity are obtained and published within 25 min after the onset of the event. First preliminary results can be obtained even within 16 min. Their rapid determination may improve the mitigation of the earthquake and tsunami hazard. Real-time application will provide rupture parameters to the GITEWS project (German Indonesian Tsunami Early Warning System). The method is applied to the two M8.0 Sumatra earthquakes on 12 September 2007, to the M7.4 Java earthquake on 2 September 2009, and to major subduction earthquakes that have occurred along Sumatra and Java since 2000. Obtained rupture parameters are most robust for the largest earthquakes with magnitudes M≥8. The results indicate that almost the entire seismogenic part of the subduction zone off the coast of Sumatra has been ruptured. Only the great Sumatra event in 2004 and the M7.7 Java event on 17 July 2006 could reach to or close to the surface at the trench. Otherwise, the rupturing was apparently confined to depths below 25 km. Major seismic gaps seem to remain off the coast of Padang and the southern tip of Sumatra.