The Diffuse Plate boundary of Nubia and Iberia in the Western Mediterranean: Crustal deformation evidence for viscous coupling and fragmented lithosphere

Palano, Mimmo; González, Pablo J.; Fernández, José

doi:10.1016/j.epsl.2015.08.040

Cited by 93 publications

(150 citation statements)

References 45 publications

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“…Previous studies of W Iberia—a region where intraplate deformation occurs at rates <1 mm/yr (Fernandes et al, ; Palano et al, )—had shown that approximately half of all earthquakes localize along clusters and lineaments, as imaged by the high‐quality recent instrumental record (1996–present) (Custódio et al, ). In this work, we carried out a detailed analysis of historical seismic data, local instrumental seismic data, and geodetic data, which indicate the existence of an active shear zone along the ASZ.…”

Section: Discussionmentioning

confidence: 98%

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An Active Seismic Zone in Intraplate West Iberia Inferred From High‐Resolution Geophysical Data

et al. 2018

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Intraplate Iberia is a region of slow lithopsheric deformation (<1 mm/yr) with significant historical earthquake activity. Recent high‐quality instrumental data have shown that small‐magnitude earthquakes collapse along clusters and lineaments, which however do not bear a clear relationship to geologically mapped active structures. In this article, we investigate the controls of these earthquake clusters. In particular, we study two of the identified clusters—the Arraiolos and the Évora seismic zones (ASZ and ESZ), located in the Western Ossa Morena Zone, southwest Iberia. The ASZ marks a sharp boundary between a seismically active region to its south and a more quiet region to its north. We revise historical earthquakes in order to clarify whether earthquake activity in the region is persistent. We use data from a local network to compute accurate epicenters, focal depth, focal mechanisms, and spatiotemporal clustering, thus characterizing ongoing small‐scale fracturing. Finally, we analyze complementary data sets, including tomographic models, Global Navigation Satellite Systems data, magnetic anomalies, and gravity anomalies, in order to discuss the factors that control seismogenesis in the two seismic zones. Consistency between earthquake locations, focal mechanisms and Global Navigation Satellite Systems data suggests that the ASZ is an active right‐lateral shear zone, which divides two blocks within the Western Ossa Morena Zone. The ESZ seems to localize microseismicity due to its granitic lithology. These results suggest that high‐resolution geophysical data have the potential to reveal blocks with different seismogenic and rheological behaviors, which may be used to improve our understanding of fault systems and the assessment of earthquake hazard in slowly deforming regions.

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Section: Discussionmentioning

confidence: 98%

“…Figure a shows surface velocities in a fixed Eurasian reference frame inferred from Global Navigation Satellite System (GNSS) (Palano et al, ). We divided the observations to the north of the ASZ (red) from those to its south (blue).…”

Section: Active Seismicity Of the Western Ossa Morena Zonementioning

confidence: 99%

An Active Seismic Zone in Intraplate West Iberia Inferred From High‐Resolution Geophysical Data

et al. 2018

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“…The Calabrian backarc (below the Tyrrhenian Sea) shows a broader stronger low P wave velocity anomaly, than the corresponding back‐arc domain from the Gibraltar subduction (below the Alboran Sea), which exhibits a thinner zone of higher‐temperature asthenosphere at shallower depths (50–150 km), and further in the backarc presents a less pronounced and more heterogeneous anomaly (Figures c and d). While the estimated modern‐day subduction velocities are very small for both subduction systems, 3–5 mm/yr for Calabria (Palano et al, , ) and ~5 mm/yr for Gibraltar (Koulali et al, ; Palano et al, ), it is thought that the Tyrrhenian Sea back‐arc basin had two major phases of opening linked to rapid slab rollback, inducing vigorous mantle convection (Faccenna et al, ). Furthermore, the larger Tyrrhenian Sea back‐arc basin evolved all the way to seafloor spreading (Marani & Trua, ), whereas the W Alboran basin, while highly extended, never reached seafloor spreading (Booth‐Rea et al, ; Medaouri et al, ; Watts et al, ).…”

Section: Discussionmentioning

confidence: 99%

Geometry of the Deep Calabrian Subduction (Central Mediterranean Sea) From Wide‐Angle Seismic Data and 3‐D Gravity Modeling

Dellong

Klingelhoëfer

Dannowski

et al. 2020

Geochem Geophys Geosyst

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The Calabrian subduction zone is one of the narrowest arcs on Earth and a key area to understand the geodynamic evolution of the Mediterranean and other marginal seas. Here in the Ionian Sea, the African plate subducts beneath Eurasia. Imaging the boundary between the downgoing slab and the upper plate along the Calabrian subduction zone is important for assessing the potential of the subduction zone to generate megathrust earthquakes and was the main objective of this study. Here we present and analyze the results from a 380‐km‐long, wide‐angle seismic profile spanning the complete subduction zone, from the deep Ionian Basin and the accretionary wedge to NE Sicily, with additional constraints offered by 3‐D gravity modeling and the analysis of earthquake hypocenters. The velocity model for the wide‐angle seismic profile images thin oceanic crust throughout the basin. The Calabrian backstop extends underneath the accretionary wedge to about 100 km SE of the coast. The seismic model was extended in depth using earthquake hypocenters. The combined results indicate that the slab dip increases abruptly from 2–3° to 60–70° over a distance of ≤50 km underneath the Calabrian backstop. This abrupt steepening is likely related to the rollback geodynamic evolution of the narrow Calabrian slab, which shows great similarity to the shallow and deep geometry of the Gibraltar slab.

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“…Although some of the station velocities have been already published elsewhere, and the overall surface kinematics is well known and discussed in several recent papers (e.g. Nocquet, 2012;Serpelloni et al, 2013;Kreemer et al, 2014;Métois et al, 2015, Palano et al, 2015, here the velocity field is represented for the first time at the Eurasian plate scale with homogeneous standards, best available spatial resolution and special care for reference frame stability. Moreover the velocity field is obtained by re-processing the whole data set with different approaches and combining the velocity fields with the aim of building on a regular basis a high level GPS product for the scientific community.…”

Section: Results: Europe-africa Boundary Zone Deformationmentioning

confidence: 99%

A Combined Velocity Field of the Mediterranean Region

Devoti

D’Agostino²,

Serpelloni³

et al. 2017

Annals of Geophysics

134

104

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The Diffuse Plate boundary of Nubia and Iberia in the Western Mediterranean: Crustal deformation evidence for viscous coupling and fragmented lithosphere

Cited by 93 publications

References 45 publications

An Active Seismic Zone in Intraplate West Iberia Inferred From High‐Resolution Geophysical Data

An Active Seismic Zone in Intraplate West Iberia Inferred From High‐Resolution Geophysical Data

Geometry of the Deep Calabrian Subduction (Central Mediterranean Sea) From Wide‐Angle Seismic Data and 3‐D Gravity Modeling

A Combined Velocity Field of the Mediterranean Region

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