Welcome to EARTHQUAKE,

EARTHQUAKE ›› 1999, Vol. 19 ›› Issue (4): 331-337.

Previous Articles     Next Articles

STRAIN SHAKING AND WAVE VELOCITY ANOMALY AND STUDIES ON FRACTURING PRECURSORY FEATURES OF COMBINED STRONG BODY

Xu Zhaoyong1), Wang Bin1), Yang Runhai1), Zhao Jinming1), Mei Shi rong2)   

  1. 1) Seis mological Bureau of Yunnan Province, Kunmi ng 650041,China;
    2) Center for Analysis and Prediction, CSB, Beijng 10036, China
  • Received:1998-10-28 Revised:1999-01-10 Online:1999-10-31 Published:2022-09-23

Abstract: Under the conditions of uniaxial compression and biaxial single-Hateral direct shearing,the authors have studied fractuning features, sudden strain shaking and wave velocity anomalies for fracturing precursors of the 3-segment-com bined sample with high and low strengths. Viewing from the variations of strains in high and low strengths, there appears sudden shaking first in the segment with low strengths (weak rock),and thenin the segment with high strength (strong rock), before the whole sample fracturing. Viewing from variations of wave velocities passing through segments with high and low strengths, there appears decrease of wave velocities first in the segment with low strength, and then in the segment with high strength. The fissures pass throughout the whole-segm ented sa mple obviously after the main fracture. Further, the authors have discussed spatial-temporal features of the sudden strain precursor and wave velocity anomalies in the seismogenic model of strong body (before main fracture).

Key words: Segmented rock sample, Fracture of strong body, Strain shaking, Ptravel timel