Application of real-time GPS to earthquake early warning in subduction and strike-slip environments
Application of real-time GPS to earthquake early warning in subduction and strike-slip environments
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DOI：
10.1002/jgrb.50242
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发表时间：
2013-07-01
影响因子：
3.9
通讯作者：
Zollo, Aldo
中科院分区：
文献类型：
--
作者：
Colombelli, Simona;Allen, Richard M.;Zollo, Aldo
我们探讨了GPS数据在地震预警中的应用，并研究了同震地面变形是否可以用来提供快速可靠的震级估计和地面震动预测。我们使用一种算法从GPS位移时间序列中提取永久静态偏移量，并反演断层面上的滑动分布，将其离散为少量的矩形块。我们开发了一种完全自适应的策略，其中的初始断层面模型是建立在一个快速的，近似的震级估计的基础上，然后允许增加的大小的基础上的演变震级估计从滑动反演。两个主要的预警输出是实时提供的：震级和断裂区的沿走向范围。最后，这些被用来预测由于有限源的预期地面震动。我们通过模拟三次地震的实时环境来测试所提出的策略。对于M-w 9.0，2011年东北冲地震，我们的算法提供了第一个震级估计8.2在39秒后的起源时间，然后逐渐增加到8.9在120秒。估计的破裂长度从一开始就保持不变，约为360公里。对于2003年十胜冲木M-w 8.3地震，24 s时的初始震级估计为8.5，40 s时降至8.2，破裂长度为290 km。最后，对于2010年El Mayor-Cucapah地震，震级估计为7.0，破裂长度为140 km。基于GPS的震级和有限范围的地面震动预测精度明显优于现有的基于地震学的点源方法。这种方法还将有助于更迅速地发出海啸警报。
We explore the application of GPS data to earthquake early warning and investigate whether the coseismic ground deformation can be used to provide fast and reliable magnitude estimations and ground shaking predictions. We use an algorithm to extract the permanent static offset from GPS displacement time series and invert for the slip distribution on the fault plane, which is discretized into a small number of rectangular patches. We developed a completely self-adapting strategy in which the initial fault plane model is built based on a quick, approximate magnitude estimation and is then allowed to increase in size based on the evolutionary magnitude estimation resulting from the slip inversion. Two main early warning outputs are delivered in real-time: magnitude and the along-strike extent of the rupture area. These are finally used to predict the expected ground shaking due to the finite source. We tested the proposed strategy by simulating real-time environments for three earthquakes. For the M-w 9.0, 2011 Tohoku-Oki earthquake, our algorithm provides the first magnitude estimate of 8.2 at 39 s after the origin time and then gradually increases to 8.9 at 120 s. The estimated rupture length remains constant from the outset at similar to 360 km. For the M-w 8.3, 2003 Tokachi-Oki earthquake, the initial magnitude estimate is 8.5 at 24 s and drops to 8.2 at 40 s with a rupture length of 290 km. Finally, for the M-w 7.2, 2010 El Mayor-Cucapah earthquake, the magnitude estimate is 7.0 from the outset with a rupture length of 140 km. The accuracy of the ground shaking prediction using the GPS-based magnitude and finite extent is significantly better than existing seismology-based point source approaches. This approach would also facilitate more rapid tsunami warnings.