The 1996 M-L=7.0 Lijian earthquake, Yunnan, China: an anticipated event

On 3 February 1996, a magnitude 7.0 earthquake took place at Lijiang, Yunna n Province of southwest China. An intermediate-term earthquake prediction f or the Jianchuan-Lijiang fault was issued in 1993 in which the magnitude, e picenter and occurrence time of the forthcoming earthquake were approximate ly given. This earthquake prediction was based on an inversion analysis of observed baseline changes from the GPS (Global Positioning System) survey o f 1988-1991 in which two active segments were found on the Red River and Ji anchuan-Lijiang faults, respectively. Here we report the methodology used i n predicting this earthquake and further investigate stress changes caused by movement of the active fault segments before the earthquake. We find tha t the aseismic fault activity during 1988-1991 resulted in significant Coul omb stress concentration at depth around the Jianchuan-Lijiang fault, and t hat the hypocenter of the 1996 Lijiang earthquake received a Coulomb failur e stress up to 2.6 bar. This study suggests that aseismic fault movement be neath the seismogenic layer may play an important role in controlling regio nal stress concentration and inducing earthquakes on surrounding faults. (C ) 1999 Elsevier Science Ltd. All rights reserved.