Toward systematic retrieval of earthquake source parameters from regional seismic waveforms

从区域地震波形中系统地检索震源参数

• 批准号: 16540385
• 负责人: KUGE Keiko
• 金额: $ 1.6万
• 依托单位: Kyoto University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16540385/
• 关键词: Earthquake; Source parameters; Seismic waveform; Regional network; Software; モーメントテンソル; すべり分布; チリ北部の地震; 震源情報; メカニズム; 震源過程; 地震波; プログラムパッケージ

Earthquakes are results of faulting in the Earth, and the characteristics of faulting are not simple in terms of fault geometry, size, and spatiotemporal distribution of displacement. In order to understand the physics controlling the complex source characteristics, it is important to accumulate a number of earthquake source parameters determined with the same technique. To attain such systematic analysis, software, which can be simple handling for anybody, is desired. In the present project, we have developed the software that can easily retrieve earthquake source parameters from regional seismic waveforms. Regional seismic networks are increasingly deployed over the world, and the waveforms include information on earthquake source characteristics that are hardly detected from teleseismic data. The software was tested for earthquakes in Turkey, Pakistan, and Chile, and provided successful results. A careful test of the software was finally done for the 2005 northern Chile, intermediate-depth earthquake. Waveform data were recorded by University of Chile using their five strong-motion accelerometers within 300 km of the epicenter, and it was a good chance for us to test our software for foreign earthquakes. The analysis generally came well. Although we met a problem from uncertainty of a velocity model in the region, we overcome the problem by relocating the earthquake with used data and adding the process to our software. Due to this improvement of the software, we believe that our software is applicable to earthquakes in many regions where velocity models are not well determined. In Turkey and Pakistan, we succeeded to estimate focal mechanisms of small earthquakes using the software, and the solutions were used to obtain the regional stress fields. The software is distributed along with its English manual. Further applications of the software to future earthquakes in the world will build up a significant database of earthquake source parameters.

地震是地球上断层活动的结果，从断层几何形状、大小和位移的时空分布来看，断层活动的特征并不简单。为了了解控制复杂震源特征的物理机制，积累大量用相同技术确定的震源参数是很重要的。为了实现这种系统分析，需要一种软件，它可以为任何人提供简单的操作。在本项目中，我们开发了一个可以方便地从区域地震波形中提取震源参数的软件。区域地震台网在世界各地的部署越来越多，其波形包括有关震源特征的信息，这些信息很难从远程地震数据中检测到。该软件在土耳其、巴基斯坦和智利的地震中进行了测试，并提供了成功的结果。该软件终于在2005年智利北部发生的中等深度地震中进行了仔细的测试。智利大学使用震中300公里范围内的五个强震加速度计记录了波形数据，这对我们来说是一个很好的机会来测试我们的软件对外国地震的预测。分析结果总体来说是好的。尽管我们在该地区遇到了速度模型不确定性的问题，但我们通过使用数据重新定位地震并将处理过程添加到我们的软件中来克服了这个问题。由于软件的这一改进，我们相信我们的软件适用于速度模型没有很好确定的许多地区的地震。在土耳其和巴基斯坦，我们使用该软件成功地估计了小震的震源机制，并利用解得到了区域应力场。该软件与其英文手册一起分发。该软件在世界未来地震中的进一步应用将建立一个重要的震源参数数据库。