Monitoring long‐term vertical seafloor displacements at the centimeter scale using a pressure gauge network in the seismogenic zone is key to understanding the real‐time strength of interplate coupling. The mobile pressure calibrator (MPC) was developed for calibrating a seafloor pressure gauge network with a resolution of less than 1 hPa/year, equivalent to about 1 cm/year. Inherent drift of the seafloor pressure gauges is estimated by comparing the raw observations between the seafloor pressure gauges and the MPC and subsequently subtracting the long‐term pressure data. In October 2018, three in situ pressure measurements were conducted to evaluate the measurement uncertainty of the MPC. The calibrator was placed adjacent to a seafloor pressure gauge, which is installed at a depth of about 1,750m in the Nankai trough offshore Japan, and measured the pressure differences between the calibrator and the seafloor pressure gauge. The drift component of the pressure gauge used inside the MPC was estimated and corrected based on calibrations performed in the laboratory before and after the in situ seafloor pressure measurements. The results indicated an uncertainty of 0.04 hPa for the in situ measurements and therefore the possibility of detecting small, long‐term seafloor displacements. We continue to compare the MPC and seafloor pressure gauge deviations over intervals of several months to years and estimate the drift of the seafloor pressure gauge.

中文翻译：

---

用于海底大地测量系统开发的移动压力校准器

使用震源区中的压力表网络监测厘米级长期垂直海底位移是了解板间耦合实时强度的关键。移动压力校准器（MPC）是为校准海底压力表网络而开发的，分辨率小于1 hPa /年，约等于1 cm /年。通过比较海底压力表和MPC之间的原始观测值，然后减去长期压力数据，可以估算海底压力表的固有漂移。2018年十月，三原位进行压力测量以评估MPC的测量不确定度。将校准器放置在海底压力计附近，该压力计安装在日本海上南海海槽中约1750m的深度，并测量校准器和海底压力计之间的压力差。基于在原位海底压力测量之前和之后在实验室进行的校准，估算并校正了MPC内部使用的压力计的漂移分量。结果表明原位不确定度为0.04 hPa测量，并因此有可能检测出较小的长期海底位移。我们将在数月至数年的时间间隔内继续比较MPC和海底压力表的偏差，并估算海底压力表的漂移。