FAULT DEFORMATION ANOMALY AND MEDIUM AND SHORT-TERM PREDICTION OF JINGTAI MS5.9 EARTHQUAKE

Wang Shuangxu; Jiang Zaisen; Chen Wensheng; Zhang Xi; Chen Bing; Zhang Sixin; Wang Jiying

doi:10.3321/j.issn:0253-3782.2001.02.005

Abstract：The time-space distribution characteristics of fault deformation anomaly in the near-source region and its outlying zone in the seismogenic process of Jingtai MS5.9 earthquake occurred on June 6, 2000 in Gansu province is studied preliminarily. The distribution scope of fault deformation anomaly before the earthquake is wide, the anomaly shape is complicated and the pattern anomalous zone of fault deformation (strain) information index is obvious. The shape and amplitude of fault deformation anomaly in different regions differ significantly, which is closely related to the tectonic location of anomaly. The fault deformation anomaly of α,β and　γ phases along the western segment of Haiyuan fault zone shows the process from the quasi-linearity to non-linearity of fault movement in the near-source region, matches the high-value anomalous area of fault deformation (strain) information index, and reflects the high strain accumulation in the seismogenic region. However, the anomaly of abrupt jump and cusp with a large amplitude occurred in the areas far from the earthquake, such as Liupanshan fault zone which is the tectonic convergent section does not reflect the strain accumulation of its location, maybe it is a sign that the regional tectonic stress field is strengthened in the seismogenic process. Based on the above-mentioned facts and combined with the preliminary summary of experiences and lessons in the medium and short-term prediction of Jingtai MS5.9 earthquake, we study and explore the application of fault deformation anomaly to earthquake judgement.