Abstract
The anomalies of electric-magnetic field and self-potential before earthquakes are important precursory phenomena. A simulating experiment study on the variations in ultra-low frequency (ULF) magnetic field and self-potential during rock cracking was carried out in a magnetic field-free space. The results revealing in detail the whole process of the occurrences of electric and magnetic anomalies are significant for understanding the microscopic mechanism of ULF electric and magnetic signals. The experiment indicated that at the initial stage the slow changes in strain, self-potential and magnetic field with small amounts appeared firstly near the source of initial cracking, and then extended as the crack developed on. In the time domain, the self-potential anomaly emerged first and ULF magnetic field changes arose then. The shape of the ULF electric and magnetic anomaly varied obviously in early-, mid- and late-term of the test. The authors attributed the pulse-like changes of self-potential to the generation and movement of the accumulated electric charges during the cracking caused by charge separation on the crack tips within the sample. While the magnetic pulses of shorter-period at the last stage of the test, may be induced by instantaneous electric current of the accumulated charge during the cracking acceleration. The technical method and the observational results of this experiment are given in detail and the microscopic mechanism of electric and magnetic precursors before earthquake are discussed in the present paper as well.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
CHEN Zi-yong, DU Xiao-quan, XU Dong-hong, et al. 1993. The observation and research on pre-earthquake electromagnetic radiation information [J]. Acta Seismologica Sinica, 6(2): 485–494.
FAN Guo-hua, YAO Tong-qi, GU Zuo-wen, et al. 1991. Geomagnetic anomalous variations before Lancang-Gengma earthquake on November 6, 1988 [J]. Acta Seismologica Sinica, 4(4): 601–610.
Fraser-Smith A C, Bernardi A, McGill P R, et al. 1990. Low-frequency magnetic field measurements near the epicenter of the M s7.1 Loma Prieta earthquake [J]. Geophys Res Lett, 17(9): 1 465–1 468.
GUO Zi-qiang, LIU Bin. 1995. Frequency properties of electromagnetic emission associated with microscopic cracking in rocks [J]. Chinese Journal of Geophysics, 38(2): 221–226.
GUO Zi-qaing, LUO Xiang-lin, QIAN Shu-qing, et al. 1999. Electromagnetic emissions during quarry blasting [J]. Chinese Journal of Geophysics, 42(6): 834–840.
HAO Jin-qi, HUANG Ping-zhang, ZHANG Tian-zhong, et al. 1990. The effect of stress on remanent magnetization of rocks [J]. Acta Seimologica Sinica, 3(4): 465–475.
HAO Jin-qi, HUANG Ping-zhang, ZHOU Jian-guo. 1993. Effect of cracking on remanent magnetization of rocks: Its implication to earthquake prediction [J]. Chinese Journal of Geophysics, 36(1): 103–113.
Hayakawa M, Tetsuya I. 2000. ULF electromagnetic precursors for an earthquake at Biak, Indonesia on February 17, 1996 [J]. Geophys Res Lett, 27(10): 1 531–1 534.
QIAN Shu-qing, CHEN Zhi-yong, LI Yan-tang, et al. 1996. Analysis of the seismo-electromagnetic anomaly before the 5.5 magnitude earthquake on 18th October, 1989 in Datong, Shanxi Province [J]. Seismological and Geomagnetic Observation and Research, 17(1): 54–60 (in Chinese).
QIAN Shu-qing, HAO Jin-qi, ZHOU Jian-guo, et al. 2001. ULF electromagnetic precursors before the 1999 Jiji, Taiwan, earthquake and the comparison with results of simulating experiments [J]. Acta Seismologica Sinica, 14(3): 342–348.
Takeuchi A, Nagahama H. 2001. Voltage-changes induced by stick-slip of granites [J]. Geophys Res Lett, 28(17): 3 365–3 368.
Varotsos P, Alexopoulos K, Lazaridou M. 1993. Latest aspects of earthquake prediction in Greece based on seismic electric signals, II [J]. Tectonophysics, 224: 1–37.
Warwick J W, Stoker C, Meyer T R. 1982. Radio emission associated with rock fracture: possible application to the great Chilean earthquake of May 22, 1960 [J]. J Geophys Res, 87(B4): 2 851–2 859.
YANG Shao-feng, CHEN Bao-sheng, DU Ai-min, et al. 1998. Abnormality of geomagnetic pulsations before earthquakes at Kashi region in Xinjiang [J]. Chinese Journal of Geophysics, 41(3): 332–341.
ZHANG De-qi, WANG Sheng-fei, LIU Fu, et al. 1997. The characters of electromagnetic radiation of South China Sea M s 6.1 earthquake [J]. Journal of Seismology, 19(2): 23–26 (in Chinese).
ZHANG Tian-zhong, HUA Zheng-xing, XU Ming-fa. 1985. Electrical resistivity changes in rock samples during fracture and frictional sliding at 1.2 kb confine pressure [J]. Acta Seismologica Sinica, 7(4): 428–433 (in Chinese).
ZHOU Xun, LIU Xiu-lan, JIN Hai-qiang, et al. 1995. Magnetic field free space for low magnetic field measurement [A]. In: CHEN Yan-tai roed-in chief. The Development of the Observational Techniques in Earth and Space Sciences— Congratulations on the 80th Birthday of Academician Qin Xinling [C]. Beijing: Seismological Press, 369–375 (in Chinese).
Author information
Authors and Affiliations
Additional information
Foundation item: Joint Seismological Science Foundation of China (95-07-434) and the MOST under contract 2001BA601B02.
Contribution No. 02FE2023, Institute of Geophysics, China Seismological Bureau.
About this article
Cite this article
Hao, Jq., Qian, Sq., Gao, Jt. et al. ULF electric and magnetic anomalies accompanying the cracking of rock sample. Acta Seimol. Sin. 16, 113–123 (2003). https://doi.org/10.1007/s11589-003-0013-x
Received:
Revised:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/s11589-003-0013-x