Gravity anomalies and crustal signature of volcano-tectonic structures of Pico Island (Azores)

Relating Crustal Structure and Stress Indicators in the Azores Islands

“…The mentioned presence of a high seismic waves velocity volume, interpreted as a crystalline intrusion of mafic (Gabbro) and ultra-mafic rocks, apparently constraining the observed seismicity and stress state, appears to corroborate the last assumption. Under the main volcanic edifices of Faial and Pico there is no clear signal of the presence of magmatic chambers, but this maybe result of to the poor coverage of seismic paths; the presence of a low-velocity anomaly is revealed, but this may be due only to the effect of a volcanic feeding system and not the presence of a magmatic chamber, something that concurs with the suggestion of Nunes et al (2006) This book is devoted to different aspects of earthquake research. Depending on their magnitude and the placement of the hypocenter, earthquakes have the potential to be very destructive.…”

Genetic Variability and Differentiation Among Populations of the Azorean Endemic Gymnosperm Juniperus brevifolia: Baseline Information for a Conservation and Restoration Perspective

“…Santa Maria is the oldest Azorean island (8 million years old); Pico, at less than 250,000 years, is the youngest (França et al 2003;Nunes et al 2006). One island is usually the result of several volcanic events that took place in the last several hundred thousand years.…”

Constraints on the structure of the crust and lithosphere beneath the Azores Islands from teleseismic receiver functions

“…The velocity models M4 to M10 are based on the first three models and the Hk-stacking results (Supporting Information Table S2), and are built to fit the pulses observed in the stacked RF by forward modelling. To steer clear of implausible models, we used estimates from active seismic and gravity studies as guidelines for the layer depths (crustal layer at roughly 3 km), velocities (∼7.6 km s −1 at about >12 km) and densities (∼2850 g cm −3 in the crust) (Steinmetz et al 1977;Montesinos et al 2003;Nunes et al 2006;Dias et al 2007). In general, the models can be divided into two classes, those with magmatic intrusions beneath the oceanic crust (underplated layer) (M2a, M6, M7a-c, M10) and those with a simple oceanic crust (M1, M2b,c, M3a,b, M4, M5, M8, M9).…”

“…Velocity model M1 is based on PEM-O (Dziewonski et al 1975). M2a and M2b are based on the velocities derived by Leahy et al (2010) with an underplated layer and without underplating, respectively; the layer depths are inferred from the literature (Searle 1976;Detrick et al 1995;Luis & Neves 2006;Nunes et al 2006;Dias et al 2007). M3 is based on the Crust1.0 velocity model at the location of CMLA (Laske et al 2013).…”