Extension of the crust generates normal faults and basins where sediments are trapped. Morphologically, extensional basins are generally classified as internally (endorheic) or externally (exorheic) drained. In the case of an internally drained basin, sediments are transported and stored within it. If the basin is externally drained, sediments are transported out of the basin and deposited in distal regions. The internally drained stage of extensional basins is generally a transient feature as these basins often evolve into an externally drained basin. Endorheic-exorheic and exorheic-endorheic transitions have been documented in several rifts basins, in compressional and extensional settings, to unravel the feedback between sedimentation-erosion-climate and tectonics (e.g.,

Minimum 1D velocity models and station corrections have been computed for the central Mediterranean area using two main data sets. The first one consists of accurate first arrival-time readings from 103 seismic events with magnitude (ML)≥3.5 recorded by the Italian National Seismic Network (RSN) and the AlpArray Seismic Network (AASN) in the period 2014–2021. Earthquakes were selected on the basis of their spatial distribution, epicentral distance to the nearest seismic station, and maximum distance traveled by Pn and Sn phases. This fine selection of high-quality data combined with the spatial density of the AlpArray seismic stations was decisive in obtaining high resolution for upper mantle velocity, especially in the Alpine belt. To obtain a denser coverage of crustal rays, we extended the first data set with P and S arrivals of local earthquakes from Istituto Nazionale di Geofisica e Vulcanologia (INGV) bulletin data (2016–2018). A total of 75,807 seismic phases (47,183 P phases and 28,264 S phases) have been inverted to calculate best-fit 1D velocity models, at regional and local scales. We then test the performance of the optimized velocity models by relocating the last four years of seismicity recorded by INGV (period 2017–2020). The computed velocity models are very effective for routine earthquake location, seismic monitoring, source parameter modeling, and future 3D seismic tomography.

<p>It has been widely recognized that the presence of seamounts can profoundly affect megathrust seismicity. With their outstanding topography, seamounts can tune interplate stress and favor the development of a fracture network in the overriding plate. Subducting seamounts can also control fluid accumulation and sediment porosity. However, their role as barriers or triggers for rupture propagation remains a matter of debate.</p> <p>In this work, we used analog models to study how geometric and frictional heterogeneities associated with a single subducting seamount influence the seismogenic behavior of the megathrust. We used four different model configurations (i.e., a flat interface, a high-friction and low-friction seamount, and a low-friction patch) to investigate both the combined and individual effect of geometry and friction.</p> <p>Our results show that low friction areas, either flat or with a seamount relief, reduce interplate coupling. Also the presence of a geometric feature tends to decrease seismic coupling and segment ruptures promoting earthquakes enucleation on the flat region. The maximum barrier efficiency is achieved with the low-friction patch model, where the accumulated stress is preferentially released by the occurrence of small earthquakes. This behavior is well suited to natural cases where seamounts are supposed to lower interplate friction due to fluid release or by the development of fracture systems development, causing microseismicity and slow slip events.</p>

The most destructive earthquakes occur along subduction megathrusts. Previous studies have shown that megathrust seismicity is influenced by different geometrical and physical parameters including interplate roughness (

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