https://scholars.lib.ntu.edu.tw/handle/123456789/614602
標題: | A mechanism for anomalous decline in radon precursory to an earthquake | 作者: | Kuo M.C.T.; Fan K.; Kuochen H.; Chen W. Fan, K. Kuochen, H. WEN-SHAN CHEN HAO KUO-CHEN |
關鍵字: | Brittle rock; Formation brine; Gas saturation; Volumetric strain; Cracks; Earthquakes; Groundwater; Porosity; Rocks; Saturation (materials composition); Radon; fresh water; radon; anomaly; background level; crust; earthquake; earthquake epicenter; groundwater; mudstone; radon; sandstone; strain measurement; thermal spring; tracer; article; chemistry; disaster; geography; phase transition; Taiwan; temperature; theoretical model; time; Disasters; Fresh Water; Geography; Models, Theoretical; Natural Disasters; Phase Transition; Radon; Taiwan; Temperature; Time Factors; Asia; Chengkung; Eurasia; Far East; Taiwan | 公開日期: | 2006 | 卷: | 44 | 期: | 5 | 起(迄)頁: | 642-647 | 來源出版物: | Ground Water | 摘要: | Mechanisms for interpreting anomalous decreases in radon in ground water prior to earthquakes are examined with the help of a case study to show that radon potentially is a sensitive tracer of strain changes in the crust preceding an earthquake. The 2003 Chengkung earthquake of magnitude (M) 6.8 on December 10, 2003, was the strongest earthquake near the Chengkung area in eastern Taiwan since 1951. The Antung radon-monitoring station was located 20 km from the epicenter. Approximately 65 d prior to the 2003 Chengkung earthquake, precursory changes in radon concentration in ground water were observed. Specifically, radon decreased from a background level of 780 pCi/L to a minimum of 330 pCi/L. The Antung hot spring is situated in a fractured block of tuffaceous sandstone surrounded by ductile mudstone. Given these geological conditions, we hypothesized that the dilation of brittle rock mass occurred at a rate faster than the recharge of pore water and gas saturation developed in newly created cracks preceding the earthquake. Radon partitioning into the gas phase may explain the anomalous decrease of radon precursory to the 2003 Chengkung earthquake. To support the hypothesis, vapor-liquid, two-phase radon-partitioning experiments were conducted at formation temperature (60°C) using formation brine from the Antung hot spring. Experimental data indicated that the decrease in radon required a gas saturation of 10% developed in rock cracks. The observed decline in radon can be correlated with the increase in gas saturation and then with the volumetric strain change for a given fracture porosity. Copyright © 2006 The Author(s). |
URI: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-33748426939&doi=10.1111%2fj.1745-6584.2006.00219.x&partnerID=40&md5=e06851042b5fc1ea0c297065ee1b757b https://scholars.lib.ntu.edu.tw/handle/123456789/614602 |
ISSN: | 0017467X | 其他識別: | GRWAA | DOI: | 10.1111/j.1745-6584.2006.00219.x |
顯示於: | 地質科學系 |
在 IR 系統中的文件,除了特別指名其著作權條款之外,均受到著作權保護,並且保留所有的權利。