DOI: 10.1016/j.earscirev.2021.103667
论文题名: The epicentral fingerprint of earthquakes marks the coseismically activated crustal volume
作者: Petricca P. ; Bignami C. ; Doglioni C.
刊名: Earth Science Reviews
ISSN: 00128252
出版年: 2021
卷: 218 语种: 英语
中文关键词: Constructive waves inferference
; Earthquake epicentral area
; InSAR coseismic vertical deformation
; Near-field active domain
; Seismic hazard assessment
英文关键词: active fault
; coseismic process
; crustal structure
; data set
; deformation mechanism
; earthquake epicenter
; earthquake mechanism
; hazard assessment
; interferometry
; seismic hazard
; seismicity
; synthetic aperture radar
; tectonic setting
英文摘要: InSAR images allow to detect the coseismic deformation, delimiting the epicentral area where the larger displacement has been concentrated. By inspecting the InSAR fringe patterns it is commonly recognized that, for dip-slip faults, the most deformed area is elliptical, or quadrilobated for strike-slip faults. This area coincides with the surface projection of the volume coseismically mobilized in the hanging wall of thrusts and normal faults, or the crustal walls adjacent to strike-slip faults. In the present work we analyzed a dataset of 32 seismic events, aiming to compare the deformation fields in terms of shape, spatial extents, and amount of deformed rock volumes, and the corresponding earthquake type and magnitudes. The dimension of the deformed area detected by InSAR scales with the magnitude of the earthquake, and we found that for M ≥ 6 is always larger than 100 km2, increasing to more than 550 km2 for M ≈ 6.5. Moreover, the comparison between InSAR and Peak Ground Accelerations documents the larger shaking within the areas suffering higher vertical deformation. As well established, the seismic epicenter rarely coincides with the area of larger shaking. Instead, the higher macroseismic intensity often corresponds to the area of larger vertical displacement (either downward or upward), apart local site amplification effects. Outside this area, the vertical displacement is drastically lower, determining the strong attenuation of seismic waves and the decrease of the peak ground acceleration in the surrounding far-field area. Indeed, the segment of the activated fault constrains the area where the vertical oscillations are larger, allowing the contemporaneous maximum freedom degree of the crustal volume affected by horizontal maximum shaking, i.e., the near-field or epicentral area; therefore, the epicentral area and volume are active, i.e., they coseismically move and are contemporaneously crossed by seismic waves (active volume and surface active domain) where trapped waves and constructive interference are expected, whereas the surrounding far-field area is mainly fixed and passively crossed by seismic waves (passive volume and surface passive domain). All these considerations point out that InSAR images of areas affected by earthquakes are a powerful tool representing the fingerprint of the epicentral area where the largest shaking has taken place during an earthquake. Seismic hazard assessments should primarily rely on the expected future active domains. © 2021 The Author(s) Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/166482
Appears in Collections: 气候变化与战略
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作者单位: Dipartimento di Scienze della Terra, Sapienza University, Rome, Italy; Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy
Recommended Citation:
Petricca P.,Bignami C.,Doglioni C.. The epicentral fingerprint of earthquakes marks the coseismically activated crustal volume[J]. Earth Science Reviews,2021-01-01,218