浙江温州4．6级地震群前宁波地震台水温异常特征讨论
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摘要
浙江温州M_L 4．6震群是宁波地震台ZK03井水温观测5年多来碰到的300 km内,第1个4．5级以上的地震事件;虽然还没有达到本学科认为的预报效能范围内的地震,但震前该台水温测值临震异常比较明显,主要表现为一个“方波”形态的异常现象,最大异常量达正常日均上升速率的30倍。异常形态与过去8级地震前有明显的不同,说明异常作用源发生了变化;据此,作了一定程度的短期预报尝试。水温出现的异常可能是孕震中断层面缓慢产生“流变体”滑动形成的长周期波,通过上地幔或软流层传播而造成的。同时,这种长周期波还可能造成观测井周边地下微裂隙张开或闭合,使地下流体发生了微小的温度变化,被高精度的测温仪器记录下来。
The Menzhou M_L 4.6 earthquake swarm is the first event that is larger than 4.5 magni- tudes and within 300 km epicenter distance during the 5 years of hydrothermal observation in ZK03 well in Ningbo Seismic Station.Although the earthquake is not stronger than the pre- diction level of this discipline,the emergency anomaly of hydrothermal measurement in the station is obvious.The anomaly shows as“square wave”with a maximum of 30 times larger than the daily rising average.The form of the anomaly is difference from that before an earthquake of 8 magnitudes,implying that the source of anomaly is changed.Based on the a- nomaly,a short-term prediction is tested.The hydrothermal anomaly may be cause by the long-periods wave,which propagates through the upper mantle or asthenosphere and arose from the slippage of rheological body generated tardily in seismogenie fault.Meanwhile,the long-periods wave may cause the micro-crack near the observation well to open or close,re- sults in tiny variation of temperature in underground fluid.The temperature variation can be recorded by the high precise thermograph.
The Menzhou M_L 4.6 earthquake swarm is the first event that is larger than 4.5 magni- tudes and within 300 km epicenter distance during the 5 years of hydrothermal observation in ZK03 well in Ningbo Seismic Station.Although the earthquake is not stronger than the pre- diction level of this discipline,the emergency anomaly of hydrothermal measurement in the station is obvious.The anomaly shows as“square wave”with a maximum of 30 times larger than the daily rising average.The form of the anomaly is difference from that before an earthquake of 8 magnitudes,implying that the source of anomaly is changed.Based on the a- nomaly,a short-term prediction is tested.The hydrothermal anomaly may be cause by the long-periods wave,which propagates through the upper mantle or asthenosphere and arose from the slippage of rheological body generated tardily in seismogenie fault.Meanwhile,the long-periods wave may cause the micro-crack near the observation well to open or close,re- sults in tiny variation of temperature in underground fluid.The temperature variation can be recorded by the high precise thermograph.
引文
①邱永平．江西九江5．7级地震前宁波台水温异常现象探讨．2005年12月,待刊稿
郭增建,秦保燕．1979．震源物理[M]．北京:地震出版社
邱永平,夏超德．2002．宁波地震台矿泉井水温异常与萨尔瓦多8．0级地震的关系[J]．华南地震,22(3):80～83
邱永平．2003．宁波ZK03井水温异常与昆仑山口西8．1级地震的关系[J]．内陆地震,17(2):141～144
邱永平．2004．宁波地震台ZK03井水温异常与日本北海道8．0级地震的关系[J]．地震地磁观测与研究,25(6):49～54
邱永平．2005．ZK03井水温异常与印尼8．7级地震的关系[J]．华北地震科学,23(4):13～16
郭增建,秦保燕．1979．震源物理[M]．北京:地震出版社
邱永平,夏超德．2002．宁波地震台矿泉井水温异常与萨尔瓦多8．0级地震的关系[J]．华南地震,22(3):80～83
邱永平．2003．宁波ZK03井水温异常与昆仑山口西8．1级地震的关系[J]．内陆地震,17(2):141～144
邱永平．2004．宁波地震台ZK03井水温异常与日本北海道8．0级地震的关系[J]．地震地磁观测与研究,25(6):49～54
邱永平．2005．ZK03井水温异常与印尼8．7级地震的关系[J]．华北地震科学,23(4):13～16
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