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| Long aftershock sequences in North China and Central US: implications for hazard assessment in mid-continents |
| Mian Liu1,2, Gang Luo3, Hui Wang4, Seth Stein5 |
1 Department of Geological Sciences, University of Missouri, Columbia, MO 65211, USA
2 The Key Laboratory of Computational Geodynamics, Chinese Academy of Sciences, Beijing 100049, China
3 Bureau of Economic Geology, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78713, USA
4 Institute of Earthquake Science, China Earthquake Administration, Beijing 100036, China
5 Department of Earth and Planetary Sciences, Northwestern University, Evanston, IL 60208, USA |
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Abstract Because seismic activity within mid-continents is usually much lower than that along plate boundary zones, even small earthquakes can cause widespread concerns, especially when these events occur in the source regions of previous large earthquakes. However, these small earthquakes may be just aftershocks that continue for decades or even longer. The recent seismicity in the Tangshan region in North China is likely aftershocks of the 1976 Great Tangshan earthquake. The current earthquake sequence in the New Madrid seismic zone in central United States, which includes a cluster of M~7.0 events in 1811–1812 and a number of similar events in the past millennium, is believed to result from recent fault reactivation that releases pre-stored strain energy in the crust. If so, this earthquake sequence is similar to aftershocks in that the rates of energy release should decay with time and the sequence of earthquakes will eventually end. We use simple physical analysis and numerical simulations to show that the current sequence of large earthquakes in the New Madrid fault zone is likely ending or has ended. Recognizing that mid-continental earthquakes have long aftershock sequences and complex spatiotemporal occurrences are critical to improve hazard assessments.
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Received: 17 September 2013
Published: 02 February 2014
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| Fund:NSF-PIRE Grant OISE-0730154 and the University of Chinese Academy of Science. Wang’s work is supported by the International Science and Technology Cooperation Program of China grant (2010DFB20190) and the National Natural Science Foundation of China (Grants Nos. 41104058 and 41104057). Gang Luo acknowledges support from the Opening Fund of State Key Laboratory of Geohazard Prevention and Geoenvironment Protection (Chengdu University of Technology) (SKLGP2012K030) |
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Corresponding Authors:
Mian Liu
E-mail: lium@missouri.edu
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