Cito Pasquale, Vitale Antonio, Iervolino Iunio
Dipartimento di Strutture Per l'Ingegneria e l'Architettura, Università degli Studi di Napoli Federico II, Via Claudio 21, 80125, Naples, Italy.
IUSS Scuola Universitaria Superiore di Pavia, Piazza della Vittoria 15, 27100, Pavia, Italy.
Sci Rep. 2024 Feb 28;14(1):4840. doi: 10.1038/s41598-024-55415-9.
Current seismic structural design makes use of a ground motion intensity that has a certain probability of being exceeded at a site of interest in a time interval or, equivalently, exceedance return period. The design intensities with the same return period are often collected in the form of maps deriving from probabilistic seismic hazard analysis (PSHA) for each of the sites of interest. Probability theory underlying PSHA dictates that, in any time interval, design intensities are expected to be exceeded in a fraction of sites that depends on the return period the map refers to. In the case of Italy, three different nationwide PSHA studies can be currently considered of relevance. In the study, the estimated areal fraction of the Italian territory exposed to exceedance of the design intensity from 2008 to 2019 was quantified for the three hazard models, based on ShakeMap data for instrumental earthquakes. In addition, the same fraction was calculated considering a sparse catalog of inferred ShakeMap for historical earthquakes that occurred over almost 1000 years. It was found that, despite the apparent differences in the hazard models, the estimated fraction of territory exposed to exceedance is comparable for all the considered hazard maps.
当前的地震结构设计采用的地面运动强度，在一个时间间隔内，在感兴趣的场地有一定的概率会被超过，或者等效地，采用超越重现期。具有相同重现期的设计强度通常以地图的形式收集，这些地图源自针对每个感兴趣场地的概率地震危险性分析（PSHA）。PSHA所基于的概率论表明，在任何时间间隔内，预计设计强度会在一定比例的场地被超过，该比例取决于地图所指的重现期。就意大利而言，目前可以认为有三项不同的全国性PSHA研究具有相关性。在该研究中，基于仪器记录地震的ShakeMap数据，针对三种危险性模型，量化了2008年至2019年期间意大利领土上预计超过设计强度的面积比例。此外，考虑到近1000年来发生的历史地震的推断ShakeMap稀疏目录，计算了相同的比例。结果发现，尽管危险性模型存在明显差异，但对于所有考虑的危险性地图，预计超过设计强度的领土比例是可比的。
