| 个人简介 | |
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 Prof. Victor Novikov Joint Institute for High Temperatures, Russian Academy of Sciences, 125412 Moscow, Russia |
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| 标题： An overview of physical mechanisms of induced and triggered seismicity: An implication for electromagnetic triggering of earthquakes and seismic hazard mitigation | |
| 摘要： A new type of earthquake triggering has been discovered during the field experiments on electromagnetic monitoring of the Earth crust resistance at the Pamir and Northern Tien-Shan regions where DC current of 0.6-3.5 kA has been injected into the crust through the grounded dipole of 4.2 km length. The spatiotemporal variation of regional seismicity just after the DC current injection has been found, that may be explained by triggering of weak earthquakes around the dipole due to interaction of electromagnetic field with stressed rocks [1]. The observed field data were confirmed in laboratory experiments at the press and shear machines, when it was demonstrated that DC current injection into the tested rock sample is resulted in sharp increase of acoustic emission (crack formation) followed by the sample failure, as well as in triggering of laboratory "earthquakes" at the spring-block models of seismogenic fault. Nevertheless, the mechanism of electromagnetic earthquake triggering is still poorly understood that prevents the practical application of obtained results to earthquake hazard mitigation based on earthquake control or short-term prediction. In this connection an analysis of various physical mechanisms of well-studied cases of induced [2] and triggered [3] seismicity for their possible application to explain the electromagnetic phenomena of earthquake triggering was carried out. As a possible candidate of a mechanism of electromagnetic/electric triggering of earthquakes we consider the Joule heating of porous fluid-saturated rocks during DC current flow through the rocks resulted in increase of fluid pore pressure and corresponding decrease of efficient rock strength followed by a rupture of the fault when it is in subcritical strain-stress state. For verification of this hypothesis, we carried out the laboratory experiments at the specialized press, where the increase of the sample deformation rate is observed during electrical processing of the sample. The experimental results are compared with numerical data calculated by COMSOL Multiphysics© software, which indicate the clear pore pressure increase due to DC current impact that may explain a triggering impact of DC current injection into the Earth crust. Possible application of obtained results for earthquake control or short-term prediction is discussed. This work was supported by the Ministry of Science and Higher Education of the Russian Federation (State Assignment No. 075-01129-23-00). References: 1. Zeigarnik, V.A., Bogomolov, L.M. & Novikov, V.A. Electromagnetic Earthquake Triggering: Field Observations, Laboratory Experiments, and Physical Mechanisms - A Review. Izv., Phys. Solid Earth 58, 30–58 (2022). https://doi.org/10.1134/S1069351322010104. 2. Kang, JQ., Zhu, JB. & Zhao, J. A review of mechanisms of induced earthquakes: from a view of rock mechanics. Geomech. Geophys. Geo-energ. Geo-resour. 5, 171–196 (2019). https://doi.org/10.1007/s40948-018-00102-z. 3. Gomberg, J., Johnson, P. Dynamic triggering of earthquakes. Nature 437, 830 (2005). https://doi.org/10.1038/437830a. | |
| 简介： Dr. Victor Novikov is a head of Laboratory of Pulsed Power Systems for Geophysics of the Joint Institute for High Temperatures of Russian Academy of Sciences, and a head of experimental group at the Research Station of Russian Academy of Sciences located at the Northern Tien Shan (Kyrgyzstan). His research interests are R&D of pulsed power systems and their application for geology and geophysics, seismicity triggered by high-power electric pulses, development of physical backgrounds of earthquake control technology and earthquake short-term prediction based on electromagnetic earthquake triggering phenomena and space weather parameters. He served as a keynote and invited speaker at the national and international conferences, symposia, and workshops. He is a member of many international geophysical organizations (AGU, EGU, SSA, JpGU). Author and co-author of over 90 publications in the areas of power engineering and geophysics. Participant of the completed Russian-Chinese cooperation project "Coupling of geomagnetic field variations and deformation processes in the Earth crust" and Principal Co-Investigator of the successfully completed Russian-Chinese cooperation project "Space weather and earthquakes" (2021-2022) supported by Russian Foundation for Basic Research and Natural Science Foundation of China. | |
