EQ-TIME

The temporal succession of earthquakes and associated seismic slip is the main driving mechanism of relief formation in tectonically active areas. Long term fault escarpment are built by the addition of earthquake increment and thus contain key information on earthquake rupture processes, where the rupture stopped and where it has propagated during those past events. The objective of our project is to understand how tectonic loading is released by the slippage of segmented fault systems, and how successive earthquakes accrue on individual faults to produce kilometer-scale displacements and tectonic landforms. A better knowledge of these processes could significantly advance our capacity to retrieve information on tectonic activity from Earth surface observations and better anticipate seismic hazard. For that purpose, we propose to 1- to constrain and compare datasets on specific fault systems of the various stage of a fault escarpment build-up from timescales ranging from 1 a to 1 Ma; 2- to identify from those comparison key information linking long term morphology and seismic rupturing pattern 3- to test observed rupturing scenario over physics-based seismic hazard models to unravel the main physical parameters that drive those scenarios. Constraining the fault slip over various time windows ranging from 10^0 to 10^6 years and encompassing spatial scales from 10^2 to 10^5 meters has been rarely achieved. To fulfil this challenge we have chosen to work in the Apennines range in Italy (host of the 2016 seismic sequence, 5 shocks Mw5 to 6.5 over 9 months) because it provides one of the most appropriate places worldwide to study long-term morphological build-up from the addition of single earthquakes. To achieve our objectives, we will merge high-resolution and complementary data acquisition with innovative modeling strategies. We will pioneered approaches and methods adapted to deforming areas with low displacement rates and complex geometries that will be applicable worldwide. EQTIME will provide important results on : constraints on slip rates and locking depth on major Apennine faults ; detection and characterization of potential tectonic transients through the seismic cycle ; mechanical functioning of the fault system during the seismic cycle, and partitioning at depth of interseismic loading versus co-seismic strain release ; constraints on landscape evolution and relief build-up in relation with temporally and spatially evolving tectonic boundary conditions ; lateral segmentation of the fault systems, including spatial mapping of persistent barriers and seismic asperities ; improved understanding and modelling of the seismic hazard in Italy.