全球地震灾害发展趋势综述

基于EM-DAT（OFDA/CRED）国际灾害数据库及美国地质勘探局（USGS）给出的数据,提取全球1970—2018年干旱、地震、极端温度、极端气候、洪水、滑坡、火山活动、火灾和块体运动9种自然灾害的相关数据,并进行综合分析,着重分析死亡人数和经济损失。分析结果表明,21世纪以来地震灾害造成的损失最大。此外,2000—2017年全球重大地震尤其是9次特大地震的分析结果显示,可有效减轻地震灾害损失的措施至少包括建立地震预警机制、建设韧性城乡、建立完善的风险排查机制。

The Review of Serious Earthquake Across the Globe

The H/V spectral ratio method based on strong motion record has been widely used in the field of earthquake engineering since it was developed; however, there are few research papers about the key steps of tapering the truncated S-wave time series and smoothing the Fourier amplitude spectrum in the strong-motion records. Based on 642 strong-motion records collected at 19 stations during Wenchuan aftershocks in Sichuan area, we illustrated some technical notes about data processing. The results show that the amplitude of the S-wave spectral ratio less than 1.0s period is higher than those calculated using the whole time series, and extracting S-wave window in calculating H/V spectral ratio is needed. The truncation of S-wave window could lead to the side lobe effect of Fourier amplitude spectrum, and the H/V spectral ratio at the low frequency part will be significantly contaminated if without tapering, which could effectively eliminate truncation error. On the basis of taking into account both the smoothing effect and the excellent accuracy of period identification, through the trial calculation of Parzen windows with different bandwidths, we consider that the 0.5Hz bandwidth is suitable for smoothing the Fourier H/V spectral ratio curve..