Advances on the avoidance zone and buffer zone of active faults

Abstract

Most destructive earthquakes occur along active faults. Abrupt dislocation of active faults in an earthquake and long-term creep during the interseismic period can cause serious damage to buildings and public facilities. Avoiding active faults from a certain distance is the most effective method to mitigate or prevent destruction induced by such disasters. In this paper, we summarize domestic and foreign research progresses on the avoidance zone of active faults and clarify the definition of fault avoidance zone composed of fault rupture zone and setback distance on two sides of the fault. The width of the avoidance zone varies with fault characteristics, geological setting, and building features. Due to different geological backgrounds and risk resistance capacity of buildings, various countries or regions have different regulations, but common point is that at least 15-m setback distance from Holocene active faults is required. The seismogenic fault dip angles of 17 historic earthquakes with different focal depths and earthquake magnitudes are compiled to further analyze their effects on the width of rupture zones. Statistically liner and trigonometric models fail to explain their correlation, although the fault dip geometrically affects the width of the rupture zone and setback distance. In order to prevent some special and important buildings from being influenced by earthquake disasters, a wider buffer zone should be considered. The distribution of co-seismic landslides along active faults in 20 records validates the rationality that the half buffer zone on one side of the faults for important buildings should at least be 3 ​km or 5 ​km. To more scientifically confirm the reasonable avoidance zone of active faults, we suggest that the width of seismic rupture zone and the damage situation of buildings should be investigated in a unified standard, and more cases and factors are required to build a more effective model of avoidance zone.