用超限率分析法研究汶川地震的前兆应变变化
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摘要
汶川地震前,姑咱台钻孔应变仪观测到频繁的周期从数分钟到数小时的脉冲变化,经过高通滤波,可看出姑咱台钻孔应变仪观测到的脉冲异常变化与汶川地震有明显的相关性。为了验证这种脉冲的异常变化与汶川地震的相关性,提出3条判断地震前兆的相关性特点,并用超限率分析法,对这种前兆异常进行了系统的、定量的分析。这种前兆现象与"地震前驱波"相去甚远,其统计特征与岩石破裂前的声发射现象类同。
Frequent pulses,whose period from minutes to hours,were recorded with the YRY-4 strainmeter at Guza station before the Wenchuan earthquake in 2008.Via high-pass filtering,strong correlation between the recorded pulses and the main shock is revealed.In order to prove,an Overrun Rate Analysis(ORA) is carried out for a systematic and quantitative examination of the abnormal changes,based on three criteria with respect to the periods for before,during and after the main shock,respectively.The phenomenon does not seem to be close to the so called precursory long-period wave preceding a macroquake but is similar to the acoustic emission prior to the fracture of rocks.
Frequent pulses,whose period from minutes to hours,were recorded with the YRY-4 strainmeter at Guza station before the Wenchuan earthquake in 2008.Via high-pass filtering,strong correlation between the recorded pulses and the main shock is revealed.In order to prove,an Overrun Rate Analysis(ORA) is carried out for a systematic and quantitative examination of the abnormal changes,based on three criteria with respect to the periods for before,during and after the main shock,respectively.The phenomenon does not seem to be close to the so called precursory long-period wave preceding a macroquake but is similar to the acoustic emission prior to the fracture of rocks.
引文
1邱泽华,石耀霖.国际钻孔应变观测的发展现状[J].地震学报,2004,26(增刊):162-168.
2 Qiu Z H,et al.On the cause of ground stress tensile pulsesobserved before the 1976 Tangshan earthquake[J].Bull.Seism.Soc.Am.,1998,88:989-994.
3邱泽华,等.四分量钻孔应变台网汶川地震前的观测应变变化[J].大地测量与地球动力学,2009,29(1):1-5.
4池顺良.从512汶川地震前后分量应变议观测到的应变异常看建设密集应变观测网络的必要[J].国际地震动态2008,已待刊.
5车用太,等.山西朔州井水位的“前驱波”记录及其讨论[J].地震学报,2002,24(2):210-216.
6王庆良,等.理解前兆异常变化机理和地震短临前兆[J].国际地震动态,2005,(5):131-144.
7陈德福.潮汐形变前驱波的时空特征[J].大地测量与地球动力学,2006,26(2):24-30.
8周龙寿,邱泽华,唐磊.汶川8.0级地震前驱波的统计检验[J].大地测量与地球动力学,2009,29(2):24-28.
9周龙寿,等.用小波及超限率方法检验大震“前驱波”[J].地震,2009,待刊.
10邱泽华,石耀霖,欧阳祖熙.四分量钻孔观测的实地相对标定[J].大地测量与地球动力学,2005,25(1):118-122.
11 Kanamori Hand Cipar J J.Focal process of the great Chil-ean earthquake on May 22,1960[J].Physics of the Earthand Planetary Interiors,1974,9:128-136.
2 Qiu Z H,et al.On the cause of ground stress tensile pulsesobserved before the 1976 Tangshan earthquake[J].Bull.Seism.Soc.Am.,1998,88:989-994.
3邱泽华,等.四分量钻孔应变台网汶川地震前的观测应变变化[J].大地测量与地球动力学,2009,29(1):1-5.
4池顺良.从512汶川地震前后分量应变议观测到的应变异常看建设密集应变观测网络的必要[J].国际地震动态2008,已待刊.
5车用太,等.山西朔州井水位的“前驱波”记录及其讨论[J].地震学报,2002,24(2):210-216.
6王庆良,等.理解前兆异常变化机理和地震短临前兆[J].国际地震动态,2005,(5):131-144.
7陈德福.潮汐形变前驱波的时空特征[J].大地测量与地球动力学,2006,26(2):24-30.
8周龙寿,邱泽华,唐磊.汶川8.0级地震前驱波的统计检验[J].大地测量与地球动力学,2009,29(2):24-28.
9周龙寿,等.用小波及超限率方法检验大震“前驱波”[J].地震,2009,待刊.
10邱泽华,石耀霖,欧阳祖熙.四分量钻孔观测的实地相对标定[J].大地测量与地球动力学,2005,25(1):118-122.
11 Kanamori Hand Cipar J J.Focal process of the great Chil-ean earthquake on May 22,1960[J].Physics of the Earthand Planetary Interiors,1974,9:128-136.
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