Using Seafloor Geodesy to Detect Vertical Deformation at the Hikurangi Subduction Zone: Insights From Self‐Calibrating Pressure Sensors and Ocean General Circulation Models
Using Seafloor Geodesy to Detect Vertical Deformation at the Hikurangi Subduction Zone: Insights From Self‐Calibrating Pressure Sensors and Ocean General Circulation Models
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DOI：
10.1029/2022jb023989
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发表时间：
2022-11
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通讯作者：
K. Woods;S. C. Webb;L. Wallace;Y. Ito;C. Collins;N. Palmer;R. Hino;M. K. Savage;D. Saffer;E. E. Davis-E.;D. Barker
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作者：
K. Woods;S. C. Webb;L. Wallace;Y. Ito;C. Collins;N. Palmer;R. Hino;M. K. Savage;D. Saffer;E. E. Davis-E.;D. Barker
海底压力传感器数据正在成为解决俯冲区近海海底垂直位移的一种很有前途的方法，特别是在应对慢滑事件时，尽管由于传感器漂移和海洋信号，这种信号很难解决。限制近海SSE滑动分布对于了解俯冲带造成的地震和海啸灾害具有重要意义。我们处理了2019年1月至10月在新西兰近海Hikurangi俯冲区获得的海底压力数据，以估计与海底阵列下方发生的大型SSE相关的垂直位移。该实验包括三个旨在消除传感器漂移的自校准传感器，这些传感器与海洋环流模型一起，对于识别和纠正在应用传统处理技术后仍留在数据中的长期海洋变异性至关重要。我们估计，压力传感器和参考点之间不同步的长周期海洋信号影响了我们推断的位移0.3-2.6厘米，这表明仅靠区域部署的参考点可能不能提供足够的海洋噪声校正。在将长周期海洋变率改正纳入处理后，我们计算了在位于Hikurangi北部的SSE近海吉斯伯恩期间的1.0-3.3厘米的隆升，以及在Hikurangi中部的霍克湾地区近海的1.1-2.7厘米的隆升。海沟附近的压力传感器探测到的一些鹰湾位移比陆上全球导航卫星系统站点探测到的滑移开始时间推迟了6周，这表明上交所发生了上倾迁移。
Seafloor pressure sensor data is emerging as a promising approach to resolve vertical displacement of the seafloor in the offshore reaches of subduction zones, particularly in response to slow slip events (SSEs), although such signals are challenging to resolve due to sensor drift and oceanographic signals. Constraining offshore SSE slip distribution is of key importance to understanding earthquake and tsunami hazards posed by subduction zones. We processed seafloor pressure data from January to October 2019 acquired at the Hikurangi subduction zone, offshore New Zealand, to estimate vertical displacement associated with a large SSE that occurred beneath the seafloor array. The experiment included three self‐calibrating sensors designed to remove sensor drift, which, together with ocean general circulation models, were essential to the identification and correction of long‐period ocean variability remaining in the data after applying traditional processing techniques. We estimate that long‐period oceanographic signals that were not synchronous between pressure sensors and reference sites influenced our inferred displacements by 0.3–2.6 cm, suggesting that regionally deployed reference sites alone may not provide sufficient ocean noise correction. After incorporating long‐period ocean variability corrections into the processing, we calculate 1.0–3.3 cm of uplift during the SSE offshore Gisborne at northern Hikurangi, and 1.1–2.7 cm of uplift offshore the Hawke's Bay area at central Hikurangi. Some Hawke Bay displacements detected by pressure sensors near the trench were delayed by 6 weeks compared to the timing of slip onset detected by onshore Global Navigation Satellite System sites, suggesting updip migration of the SSE.