Towards a geodetic earthquake catalogue for Central America: detecting coseismic deformation in Costa Rica using Sentinel-1 InSAR
Towards a geodetic earthquake catalogue for Central America: detecting coseismic deformation in Costa Rica using Sentinel-1 InSAR
复制标题
建立中美洲大地地震目录：使用 Sentinel-1 InSAR 检测哥斯达黎加的同震变形
DOI：
10.1093/gji/ggae021
复制
发表时间：
2024
影响因子：
2.8
通讯作者：
Araya M
中科院分区：
文献类型：
--
作者：
Araya M
震源参数可以通过地震观测来估计，但由于位置的不确定性和节面之间固有的模糊性，导致识别故障变得复杂。卫星干涉合成孔径雷达（干涉合成孔径雷达）可用于观测地面变形和模拟断层几何形状，但受到气候条件（水蒸气）和地面覆盖（密集植被）的限制。在热带地区，大气是动态的，大多数地区植被茂密，使检测同震变形具有挑战性。在这里，我们进行了系统的检查同震干涉从哨兵-1 SAR图像，以评估其适用于检测同震变形在哥斯达黎加。利用地震台网的数据，我们确定了2016年至2020年之间的7次地震，深度和震级为Mw5.3 -6.2。对于每个事件，我们使用地震参数来计算视线位移上升和下降的几何形状和两个节面，并生成12-和24-D同震干涉图可用。我们获得了七个地震中的三个地震的同震位移信号干涉图。我们反演大地测量数据来检索震源参数，但缺乏近海大地测量覆盖导致参数和大的不确定性之间的权衡。Jacó和戈尔菲托地震可能发生在俯冲界面上，大地测量位置比以前的地震估计更靠近海岸6-9公里。布里卡地震发生在外弧前的一个浅陡倾逆冲断层上。对于其他地震，由于大气噪声或相干性差，没有检测到同震形变。这些结果表明，12-d Sentinel-1干涉图适用于监测中美洲Mw5.7级以上的浅源地震。这种方法可用于开始编制该区域的地表变形目录，这最终将有助于增进对活跃变形过程的了解，并改进灾害地图。
Earthquake source parameters can be estimated using seismological observations, but the identification of the fault responsible is often complicated by location uncertainties and the inherent ambiguity between nodal planes. Satellite Interferometric Synthetic Aperture Radar (InSAR) can be used to observe ground deformation and model fault geometry but is limited by climate conditions (water vapour) and ground coverage (dense vegetation). In the tropics, the atmosphere is dynamic and most regions are densely vegetated, making detecting coseismic deformation challenging. Here, we perform a systematic inspection of coseismic interferograms from Sentinel-1 SAR images, to assess their suitability for detecting coseismic deformation in Costa Rica. Using data from the seismological network, we target seven earthquakes between 2016 and 2020 with depthskm and magnitudesMw5.3–6.2. For each event, we use the seismic parameters to compute line-of-sight displacements for ascending and descending geometries and for both nodal planes and generate 12- and 24-d coseismic interferograms where available. We obtain interferograms with coseismic displacement signals for three of the seven earthquakes. We invert the geodetic data to retrieve the earthquake source parameters but the lack of offshore geodetic coverage causes trade-offs between parameters and large uncertainties. The Jacó and Golfito earthquakes likely occurred on the subduction interface and the geodetic locations were 6–9 km closer to the coast than previous seismic estimates. The Burica earthquake occurred on a shallow steeply dipping thrust fault in the outer forearc. For the other earthquakes, no coseismic deformation was detected due to atmospheric noise or poor coherence. These results demonstrate the suitability of 12-d Sentinel-1 interferograms for monitoring shallow earthquakes of magnitude >Mw5.7 in Central America. This approach can be used to begin a surface deformation catalogue for the region, which will ultimately help improve the understanding of active deformation processes and improve hazard maps.