Replacement of temperature loggers in CORKed ODP boreholes off Costa Rica and analysis of long-term temperature records

自2002年以来，海洋钻孔的长期温度和压力监测一直是一项更大的协调努力的一部分，目的是调查通过哥斯达黎加尼科亚半岛俯冲带棱镜脚趾的俯冲通量和流体流动。我们目前的目标是在微型温度记录仪(MTL)超出存储容量(2009年8月)之前恢复它们，用新的MTL取而代之，以确保下一个十年连续的温度数据，并下载密封井眼的循环观测改装工具包(CORK)-II记录的压力数据。随后，将利用随后四年的新的温度和压力数据，对时间序列的头两年得出的关于边界地区水文的暂定结论进行验证。具体地说，我们预计将对陆上全球定位系统(GPS)和地震网络探测到的与慢滑事件相关的瞬时温度和压力事件进行新的观测。在温度和压力数据分析中，潮汐引起的变化--由频率分析分开--提供有关水文地层参数的信息，其余信号表示前缘俯冲带的水文状态。除了慢滑事件，未来的MTL和CORK数据还可能记录一次大地震(MW&GT；7：5)的响应，预计这是一系列历史事件(1853、1900和1950)之一。

Since 2002, long-term temperature and pressure monitoring in marine boreholes have been part of a larger coordinated effort to investigate subduction fluxes and fluid flow through the toe of the subduction-zone prism off Nicoya Peninsula, Costa Rica. Our immediate goals are to recover miniaturized temperature loggers (MTLs) before their memory capacity is exceeded (August 2009), to replace them with new MTLs that will ensure continuous temperature data for the next decade, and to download pressure data recorded by Circulation Obviation Retrofit Kit (CORK)-IIs that seal the boreholes. Subsequently, tentative conclusions regarding the hydrology across the margin—based on the first two years of the time series—will be verified using the new temperature and pressure data of the following four years. Specifically, we anticipate new observations of transient temperature and pressure events correlated with slow slip events that have been detected by onshore Global Positioning System (GPS) and seismic networks. In temperature and pressure data analysis, tidally induced variations—separated by frequency analysis—provide information about hydrological formation parameters and the remaining signal represents the hydrological state of the frontal subduction zone. In addition to slow slip events, future MTL and CORK data may also document the response of a large earthquake (Mw >7:5) that is anticipated as one of a sequence of historical events (1853, 1900, and 1950).