Separating Sea and Slow Slip Signals on the Seafloor
Separating Sea and Slow Slip Signals on the Seafloor
复制标题
分离海底的海水信号和慢滑移信号
DOI：
10.1029/2019jb018285
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
S. Chiswell
中科院分区：
文献类型：
--
作者：
J. Gomberg;S. Hautala;P. Johnson;S. Chiswell
海底压力测量有希望从海底断层的瞬时慢滑事件中估计垂直位移。我们评估的准确性的压力偏移估计，在几天到几个星期的演变和信心，他们可能归因于构造变形或海洋水柱。解决这种模糊性的一种常见方法假设研究区域内的水柱压力变化不大，并且由稳定的参考点压力表示。评估这一假设的有效性需要独立的证据。在Hikurangi海底震颤和慢滑实验调查期间收集的压力和同位温度之间的相关性表明，温度可能为水柱压力提供有用的独立代理。我们比较了使用几种方法估计的补偿，包括温度和其他代理。使用温度代用指标并不成功，因为海底温度没有跟踪季节性信号，而季节性信号在缓慢滑动事件期间对海底压力变化有重大影响。无论采用哪种估计方法，偏移量都会在某个不确定的参考水平周围几厘米内变化。常用的统计措施不被证明是可靠的指标偏移精度，因为偏移的贡献最小的总方差。使用相同的方法估计的偏移量，但使用区域海洋模型模拟海底压力，大于从数据中得出的偏移量，但模式相似。由于该模型只模拟水柱过程，这表明很大一部分估计的压力偏移是由于季节性水柱信号，而不是构造起源。
Seafloor pressure measurements hold promise for estimating vertical displacements from transient slow slip events on submarine faults. We assess the accuracy of pressure offset estimates that evolve over days to weeks and the confidence with which they may be attributed to tectonic deformation or to the ocean water column. One common approach to resolve this ambiguity assumes water column pressures vary insignificantly over the study region and are represented by stable reference site pressures. Assessing the validity of this assumption requires independent evidence. Correlations between pressures and colocated temperatures collected during the Hikurangi Ocean Bottom Investigation of Tremor and Slow Slip experiment suggest temperatures might provide a useful independent proxy for water column pressures. We compared offsets estimated using several methods, with temperature and other proxies. The use of a temperature proxy was unsuccessful, because seafloor temperatures did not track the seasonal signal that contributes significantly to seafloor pressure changes over the slow slip event period. Regardless of the estimation method, offsets varied within a few cm around some uncertain reference level. Commonly used statistical measures are shown not to be reliable indicators of offset accuracy since offsets contribute minimally to the total variance. Offsets estimated using identical methods but with seafloor pressures simulated using a regional ocean model were larger than those derived from the data but had a similar pattern. Since the model simulates only water column processes, this suggests a significant fraction of the estimated pressure offsets are due to seasonal water column signal and are not of tectonic origin.
影响因子：
64.8
作者：
Schurr, Bernd;Asch, Guenter;Vilotte, Jean-Pierre
通讯作者：
Vilotte, Jean-Pierre