BEHAVIOR OF PEAK VERTICAL ACCELERATION ACROSS SMALL TWO-DIMENSIONAL STRONG-MOTION ARRAY

IN ORDER TO ISOLATE THE EFFECTS OF SITE PARAMETERS ON THE RECORDED VERTICAL GROUND MOTION IN THE NEAR-SOURCE REGION OFSTRONG EARTHQUEAKES, THE VERTICAL ACCELERATION TIME HISTORIES ACROSS A DENSE TWO-DIMENSIONAL ARRAY ARE BEING ANALYZED. THE EARTHQUAKE EPICENTER IS LOCATED APPROXIMATELY35 KM FROM THE CENTER OF THE ARRAY. THE INNER RING OF SMART-1 ARRAY IN TAIWAN, PROVIDING 12 ACCELEROGRAMS WITHIN ARADIUS OF 200 METERS ALLOWS FOR EXAMINATION OF FREQUENCIES AS HIGH AS 10 HZ AND IS, THEREFORE, SUITABLE FOR THE EXPERIMENT. SEISMOGRAMS ARE SUBJECTED TO BOTH TIME AND FREQUENCY DOMAIN ANALYSIS IN ORDER TO DETERMINE (A) THE NATURE OF SEISMIC PHASES(S) ASSOCIATED WITH PEAK ACCELERATION, (B) THE ASSOCIATED DOMINANT FREQUENCIES AND (C) POSSIBLE CORRELATION OF THE DOMINANT FREQUENCIES AND THEIR PEAK VALUES WITH THE KNOWN VARIATIONS OF SUBSURFACE PARAMETERS.