Abstract The 2016 Mw 7.8 Kaikōura earthquake represents an extremely complex event involving over ten major crustal faults, altering conventional understanding of multi-fault ruptures. Although evidence for coseismic slip on the Hikurangi subduction interface is controversial, we present afterslip on the subduction zone beneath Marlborough using 13 months of Interferometric Synthetic Aperture Radar (InSAR) and Global Positioning System (GPS) observations. The spatially and temporally correlated atmospheric errors in SAR interferograms are problematic, and hence a new InSAR time series approach, combining the Generic Atmospheric Correction Online Service (GACOS) with a spatial-temporal Atmospheric Phase Screen (APS) filter to facilitate the InSAR time series analysis, is developed. For interferograms with over 250 km spatial extent, we achieve a 0.77 cm displacement RMS difference against GPS, improving 61% from the conventional InSAR time series method (TS). Comparisons between the overlapping region of two independent tracks show an RMS difference of 1.1 cm for the TS-GACOS-APS combined method, improving 54% from the TS method and 27% from using TS with an APS filter only. The APS filter reduces the short wavelength residuals substantially, but fails to remove the long wavelength error even after the ramp removal, revealing that the GACOS correction has played a key role in mitigating long wavelength atmospheric effects. The resultant InSAR displacements, together with the GPS displacements, are used to recover the time-dependent afterslip distribution on the Hikurangi subduction interface, which provides insights for reviewing the co-seismic slip sources, the present status of the subduction plate boundary and future seismic hazards.

中文翻译：

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2016 年凯库拉地震后从 InSAR 时间序列和大气校正在 Hikurangi 俯冲界面南部触发的后滑

摘要 2016 年 7.8 级凯库拉地震是一个极其复杂的事件，涉及十多个主要地壳断层，改变了对多断层破裂的传统理解。尽管 Hikurangi 俯冲界面上的同震滑动证据存在争议，但我们使用 13 个月的干涉合成孔径雷达 (InSAR) 和全球定位系统 (GPS) 观测结果展示了马尔堡下方俯冲带的后滑动。SAR 干涉图中空间和时间相关的大气误差是有问题的，因此一种新的 InSAR 时间序列方法，将通用大气校正在线服务 (GACOS) 与时空大气相位屏幕 (APS) 滤波器相结合，以促进 InSAR 时间序列分析，开发。对于空间范围超过 250 公里的干涉图，我们达到了 0。77 cm 位移 RMS 与 GPS 的差异，比传统的 InSAR 时间序列方法 (TS) 提高了 61%。两个独立轨道重叠区域之间的比较显示，TS-GACOS-APS 组合方法的 RMS 差异为 1.1 cm，比 TS 方法提高了 54%，比仅使用带有 APS 滤波器的 TS 提高了 27%。APS 滤波器显着减少了短波长残差，但即使在斜坡消除后也无法消除长波长误差，这表明 GACOS 校正在减轻长波长大气效应方面发挥了关键作用。合成的 InSAR 位移与 GPS 位移一起用于恢复 Hikurangi 俯冲界面上随时间变化的后滑动分布，这为审查同震滑动源提供了见解，