Effect of Cold Wave on Geodynamical Mechanism of Borehole Volumetric Strain
China frequently experiences cold waves,but the response of borehole dilatometers to these events remains poorly understood.Between November 27 and December 1,2022,a typical cold wave was recorded,resulting in significant changes in air temperature,barometric pressure,and borehole volumetric strain measurements in Jiangsu Province.To systematically analyze strain disturbances associated with this cold wave,we employed signal processing techniques and an atmospheric loading model,focusing on observations from five borehole dilatometer stations in Jiangsu.The results show that:①The cold wave caused abrupt and widespread variations in air temperature and barometric pressure.Air temperatures dropped by up to 17.51℃,while barometric pressure surged by a maximum of 29.23 hPa.②The primary driver of significant compression changes detected by borehole dilatometers was barometric pressure.These transient strains persisted for durations ranging from 2,612 to 3,454 minutes,with maximum amplitudes reaching 174.57 nstrains.The transient strain patterns closely mirrored the variations in barometric pressure.③Non-periodic barometric responses exhibited phase delays at the Xuzhou,Lianyungang,Nantong,and Liyang stations,with delay times ranging from 52 to 306 minutes.In contrast,a 92-minute phase lead of barometric response was observed at the Xinyi station.These results provide valuable insights into transient noise caused by cold waves,contributing to the improved scientific identification of such disturbances.
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