摘要
Influenced by the layout of seismic network and the location of earthquakes,earthquake catalogs are often incomplete;such incompleteness of earthquake catalogue directly affects the analysis of sequence activity characteristics.In this paper,the GPU-acceleration-based g template matching method is used to scan the continuous waveforms of Chang Island earthquake swarm in Shandong Province from February 9 to August 20,2017.In total,15,286 earthquakes events were detected,which was more than 6 times compared with those in network catalogue and thus reduced the magnitude of completeness from 1.0 to 0.5.Based on the intergrated catalogue of earthquakes,the characteristics of Chang Island earthquake swarm were then analyzed using the Epidemic Type Aftershock Sequences(ETAS)model.The stochastic components in the ETAS model are used as a proxy for possible earthquake triggered by external forces(fluids).The results show that the proportion of earthquakes triggered by external forces of Chang Island swarm increases gradually(from 31.9%to 63.5%)and then decreases.The latter stage of swarm development is mainly affected by the self-excitation of earthquakes,suggesting that the fluids play an important role in the development of the Chang Island swarm.However,the triggering intensity of fluids to microseismicity is divergent in different periods,which may be related to the process of fluid permeation.
Influenced by the layout of seismic network and the location of earthquakes,earthquake catalogs are often incomplete; such incompleteness of earthquake catalogue directly affects the analysis of sequence activity characteristics. In this paper,the GPU-acceleration-based g template matching method is used to scan the continuous waveforms of Chang Island earthquake swarm in Shandong Province from February 9 to August 20,2017. In total,15,286 earthquakes events were detected,which was more than 6 times compared with those in network catalogue and thus reduced the magnitude of completeness from 1. 0 to 0. 5. Based on the intergrated catalogue of earthquakes,the characteristics of Chang Island earthquake swarm were then analyzed using the Epidemic Type Aftershock Sequences (ETAS) model. The stochastic components in the ETAS model are used as a proxy for possible earthquake triggered by external forces (fluids). The results show that the proportion of earthquakes triggered by external forces of Chang Island swarm increases gradually (from 31. 9% to 63. 5%) and then decreases. The latter stage of swarm development is mainly affected by the self-excitation of earthquakes,suggesting that the fluids play an important role in the development of the Chang Island swarm. However,the triggering intensity of fluids to microseismicity is divergent in different periods,which may be related to the process of fluid permeation.
基金
sponsored by the National Key R&D Program of China(2016YFE0109300)
the Seismological Science and Technology Spark Program(XH18026Y)
Natural Science Foundation of Shandong Province(ZR2017QD014)
Key R&D Program of Shandong Province(2016GSF120011)
