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Dynamics of the Seismicity in the Alto Tiberina Fault System revealed by a High-Resolution Template Matching Catalog
  • David Essing,
  • Piero Poli
David Essing
Institut des Sciences de la Terre, Université Grenoble Alpes

Corresponding Author:[email protected]

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Piero Poli
Université Grenoble-Alpes, Isterre Laboratory, CNRS
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Abstract

The Alto Tiberina Fault system located in the Northern Apennines (Italy) consist of a low angle normal fault which radiates micro-seismicity on a constant rate and is assumed to host continuous creep. In the hanging wall, on top of the low angle normal fault, a network of syn- and antithetic high angle faults frequently hosts swarm seismic sequences, one of which has been associated to a transient aseismic deformation signal. To study in detail the dynamics related to the seismic and its relationships with aseismic deformation processes occurring in this fault system, we apply template matching on seismic data recorded at an array of borehole stations, to derive a high-resolution earthquake catalog. We then quantify the time and space clustering of the seismicity which reveals elevated clustering within the hanging wall during an aseismic deformation period. This reflects the complex evolution of aseismic slip together with the complexity of the shallow fault system. On the other hand, we observe a bimodal seismicity along the low angle normal fault, with continuous and diffuse seismicity, and rapid bursts which could suggest rapid fluid releases. Along the low angle normal fault, we additionally identify repeating earthquakes and model them assuming a creep model. Our results open the possibility for other models than the actual model of inter-seismic deformation to explain the seismicity along the Alto Tiberina low angle normal fault.