Evaluation of intensity of 13 December 1996 Yeongweol earthquake and attenuation properties of Korean peninsula

1996년 12월 13일 영월지진의 진도평가와 한반도의 지진에너지감쇠 특성

For 262 locations throughout the southern part of Korean peninsula, intensities of 13 December 1996 Yeongweol earthquake are estimated to make an isoseismal map and investigate attenuation properties in the southern part of Korea. Due to the inherent uncertainties in the estimation of intensities, obtained intensity map show quite scattered pattern of intensity distribution. Estimated intensities range from III to possibly Ⅷ. In case of intensity larger than Ⅵ, considerable damages such as fracturing of walls are reported one of the most significant feature of the intensity map is, considering its magnitude 4.7 reported by KMA, the felt area is appeared to be unusually large covering most of the Korean peninsula except Cheju island. This result indicates ether the magnitude is underestimated or the focus of this earthquake is much deeper. Assuming shallow(less than 10km) intraplate earthquake, we obtained average magnitude 5.6 by using the area encircled by isoseismal contour lines from intensity IV to intensity Ⅶ. This ambiguity can be clarified if more reliable focal depth is estimated by using teleseismic earthquake records in the future.