Lithospheric structure below seismic stations in Cuba from the joint inversion of Rayleigh surface waves dispersion and receiver functions

Abstract

The joint inversion of Rayleigh wave group velocity dispersion and receiver functions has been used to study the crust and upper mantle structure at eight seismic stations in Cuba. Re- ceiver functions have been computed from teleseismic recordings of earthquakes at epicentral (angular) distances in the range from 30◦ to 90◦ and Rayleigh wave group velocity dispersion relations have been taken from earlier surface wave tomographic studies in the Caribbean area. The thickest crust (∼30 km) below Cuban stations is found at Cascorro (CCC) and Mais ́ı (MAS) whereas the thinnest crust (∼18 km) is found at stations R ́ıo Carpintero (RCC) and Guanta ́namo Bay (GTBY), in the southeastern part of Cuba; this result is in agreement with the southward gradual thinning of the crust revealed by previous studies. In the crystalline crust, the S-wave velocity varies between ∼2.8 and ∼3.9 km s–1 and, at the crust–mantle transition zone, the shear wave velocity varies from ∼4.0 and ∼4.3 km s–1. The lithospheric thickness varies from ∼65 km, in the youngest lithosphere, to ∼150 km in the northeastern part of the Cuban island, below Mais ́ı (MAS) and Moa (MOA) stations. Evidence of a subducted slab possibly belonging to the Caribbean plate is present below the stations Las Mercedes (LMG), RCC and GTBY whereas earlier subducted slabs could explain the results obtained below the Soroa (SOR), Manicaragua (MGV) and Cascorro (CCC) station

Crustal structure of western Hispaniola (Haiti) from a teleseismic receiver function study

“…9) is known to be a part of the Great Arc of the Caribbean (Burke, 1988), an inactive intra-oceanic island arc formed in the Cretaceous at the boundary of the Pacific domain and the proto-Caribbean oceanic crust (Pindell et al, 2006). The Moho depth values we compute are ranging between 20.1 km and 28.2 km, providing an average crustal thickness of 23 ± 3 km in agreement with the values found in southern Cuba (approximately 20 km, Moreno et al, 2002;González et al, 2012) and eastern Hispaniola (about 24 km, Nuñez et al, 2015). Furthermore, our results delineate the southwestern limit of the island arc domain.…”

“…Velocity model and receiver functions studies made by Moreno et al (2002) and González et al (2012) show that the depth of the Moho is approximately 20 km in the south of Cuba. In eastern Hispaniola, a seismic refraction study shows that the Moho is at approximately 24 km depth, and reaches roughly 30 km deep in the central part of Hispaniola (Nuñez et al, 2015).…”

Is the local seismicity in western Hispaniola (Haiti) capable of imaging northern Caribbean subduction?

“…These depths of 28 and 23 km do not seem to correspond to crustal fault activity. Indeed, receiver functions studies made by González et al (2012) and Corbeau et al (2017) show that Moho is at ~20 km in the south of Cuba and 23 km in the north of Haiti. This activity under the Moho could be the effect of a slab edge push (van Benthem et al, 2014).…”

Joint inversion of receiver functions and dispersion data for crustal study at VLC seismographic station (Italy)

“…The initial models (Fig. 3) of the linear joint inversion procedure are the set of models determined by the nonlinear ''hedgehog'' inversion of the cellular dispersion curves in the Italic region as described by González et al (2012), which correspond to the cells where the stations are located. In comparison with the LSO solution of hedgehog non-linear inversion (Fig.…”

“…The underlying mantle presents two lithospheric layers, thickening westward down to a depth of about 160 km in cell d0 with V S about 4.70 km/s. Such models are chosen because they fulfil the following conditions: (1) the stations are within cells, whose models are defined with adequate resolution, located in the region studied by surface wave tomography (González et al 2012).…”