Scattering and absorption imaging of a highly fractured fluid-filled seismogenetic volume in a region of slow deformation  

作　　者：Ferdinando Napolitano Luca De Siena Anna Gervasi Ignazio Guerra Roberto Scarpa Mario La Rocca 

机构地区：[1]Dipartimento di Fisica“E.R.Caianiello”,Universita Degli Studi di Salerno,Via Giovanni Paolo II,Fisciano,SA,84084,Italy [2]Institute of Geosciences,Johannes Gutenberg University Mainz,J.-J.-Becher-Weg 21,Mainz,D-55128,Germany [3]University of Aberdeen,School of Geosciences,Geology and Petroleum Geology,Meston Building,King’s College,Aberdeen,Scotland,AB243UE,UK [4]Dipartimento di Biologia,Ecologia e Scienze Della Terra,Universit a Della Calabria,Ponte P.Bucci,Arcavacata di Rende,CS,87036,Italy [5]Istituto Nazionale di Geofisica e Vulcanologia,Sezione di Rende(CS),Ponte P.Bucci,Arcavacata di Rende,CS,87036,Italy

出　　处：《Geoscience Frontiers》2020年第3期989-998,共10页地学前缘（英文版）

摘　　要：Regions of slow strain often produce swarm-like sequences,characterized by the lack of a clear mainshockaftershock pattern.The comprehension of their underlying physical mechanisms is challenging and still debated.We used seismic recordings from the last Pollino swarm(2010-2014) and nearby to separate and map seismic scattering(from P peak-delays) and absorption(from late-time coda-wave attenuation) at different frequencies in the Pollino range and surroundings.High-scattering and high-absorption anomalies are markers of a fluid-filled fracture volume extending from SE to NW(1.5-6 Hz) across the range.With increasing frequency,these anomalies approximately cover the area where the strongest earthquakes occurred from the sixteenth century until 1998.In our interpretation,the NW fracture propagation ends where carbonates of the Lucanian Apennines begin,as marked by a high-scattering and low-absorption area.At the highest frequency(12 Hz) the anomalies widen southward in the middle of the range,consistently marking the faults active during the recent Pollino swarm.Our results suggest that fracture healing has closed small-scale fractures across the SE faults that were active in the past centuries,and that the propagation of fluids may have played a crucial role in triggering the 2010-2014 Pollino swarm.Assuming that the fluid propagation ended at the carbonates barrier in the NW direction,fractures opened new paths to the South,favoring the nucleation of the last Pollino swarm.Indeed,the recently active faults in the middle of the seismogenic volume are marked by a high-scattering and highabsorption footprints.Our work provides evidence that attenuation parameters may track shape and dynamics of fluid-filled fracture networks in fault areas.

关 键 词：POLLING Seismic attenuation SCATTERING FLUIDS FRACTURES HEALING 

分 类 号：P315[天文地球—地震学]