关键词: 隐形断层, 显微构造, 第四纪松散沉积物, 古地震

Abstract: Invisible faults often developed in Quaternary unconsolidated sediments including concealed faults and die-out faults, which lead to complexity and multi-solution for paleoearthquake research. In this paper, original-state directional samples related to invisible or die-out faults are collected from some typical paleoearthquake profiles and solidified in laboratory. Microstructures have been observed after grinding slides in three-dimension coordinate system. Some indicators of invisible faults have been found in micrscopic field. The mechanisms of die-out faults have also been studied. It is suggested that according to microstructural observation, to confirm or negate the existence of concealed faults or to trace the terminated levels of die-out faults, can help us determine the age and periods of paleoearthquake events more accurately combining with macroscopic observation and age dating.

Key words: Invisible fault, Microstructure, Quaternary unconsolidated sediments, Paleoearthquake