Differential Interferogram Of The September 16 2018 Mw 5.3 Earthquake Lake Muir, Perth, Australia

A moderate earthquake of Mw 5.3 (M_L 5.7) occured on September 16 2018 near the Lake Muir region, Perth, SW Australia. Despite Australia being in a mostly stable continental interior, moderate or strong shallow crustral earthquakes occured the past years. Due to shallow faulting and low relief/semi-arid conditions in most regions of Australia, even moderate events lead to surficial deformation in form of mapped surface ruptures or deformation identified by radar satellites (InSAR). The Sep.16 earthquake produced a distinctive surficial deformation pattern, identified in an interferometric pair of Sentinel-1 Copernicus radar images (Descending orbit, September 14 - September 26). Sentinel-1 TOPS Interferogram and Line-of-Sight (LOS) displacement were produced using SNAP and DIAPASON tools in the Geohazards Exploitation Platform. Color fringes on interferogram represent each a ~2.8cm displacement. Displacement (unwrapped) grid files are also provided. InSAR analysis show co-seismic rupture along a NNE-SSW reverse fault plane, consistent with published moment tensors (USGS). LOS profiles show a 5-15cm displacement across a fault rupture that propagated to the surface. Hundreds of metres of fractures and surface ruptures were reported by local farmers' accounts and photographs to the ABC South West Australia news agency.2018年9月16日，澳大利亚西南部珀斯附近的缪尔湖（Lake Muir）区域发生了矩震级（Mw）5.3级（地方震级M_L 5.7）的中等强度地震。尽管澳大利亚大多处于稳定的大陆内部区域，但近年来仍发生过中等至强震级的浅部地壳地震。由于澳大利亚多数区域存在浅部断层活动以及低起伏/半干旱的环境条件，即便中等强度的地震事件也会引发地表变形，表现为已测绘的地表破裂，或是通过干涉合成孔径雷达（InSAR）识别出的形变。 此次9月16日的地震形成了独特的地表形变模式，可通过一对哨兵-1号（Sentinel-1）哥白尼（Copernicus）计划雷达影像的干涉对（降轨轨道，9月14日—9月26日）识别。研究人员借助地质灾害应用平台（Geohazards Exploitation Platform）中的SNAP与DIAPASON工具，生成了哨兵-1号TOPS干涉图与视线向（Line-of-Sight, LOS）位移场。干涉图上的每一条彩色条纹对应约2.8厘米的位移量。本次数据集还附带了相位解缠后的位移网格文件。 干涉合成孔径雷达（InSAR）分析结果显示，此次同震破裂沿北北东—南南西向的逆冲断层面发育，这与美国地质调查局（USGS）发布的矩张量结果一致。视线向（LOS）位移剖面显示，延伸至地表的断层破裂带的地表位移量为5至15厘米。当地农户向澳大利亚广播公司（ABC）西南澳大利亚分社提供了口述记录与实拍照片，记录了长达数百米的裂缝与地表破裂现象。