Person: Buforn Peiró, Vicenta María Elisa
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First Name
Vicenta María Elisa
Last Name
Buforn Peiró
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Físicas
Department
Física de la Tierra y Astrofísica
Area
Física de la Tierra
Identifiers
8 results
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Item From an atomistic study of olivine under pressure to the understanding of the macroscopic energy release in earthquakes(Geosystems and Geoenvironment, 2023) López Sánchez, Carolina; Mattesini, Maurizio; Buforn Peiró, Vicenta María Elisa; Udías Vallina, Agustín; Serna Valdés, Jaime de la; Talavera, Hernando; Pro, CarmenWe present a multi-disciplinary study of the rupture process of deep- and intermediate-depth earthquakes in the subducting slab that develops beneath the Peruvian-Brazilian region. This contemplates the understanding of the atomistic fracture mechanism in an olivine model, its energetics budget, and the bridging of these results to the available seismic observables. A theoretical description of the stress-strain curves for the subducting material is initially provided as a key element to discern whether the rupture mechanism changes with depth or not. To this purpose, atomistic modelling was carried out through ab initio techniques for the forsterite olivine at different pressure ranges. The achieved stress-strain curves were compared to the average moment-scaled functions obtained for 43 intermediate (50 km < h < 200 km) and very deep earthquakes (500 km < h < 700 km) at the Peruvian-Brazilian subduction zone. It is found that at both depths operate a common atomistic rupture mechanism that is based on the gliding of the {001} crystal planes. Although the velocity of stress release changes with depth, this finding helps to clarify the controversial rupture process for very deep earthquakes at subduction zones. Likewise, efforts were directed to quantify the total amount of energy freed during an earthquake. Test calculations were carried out for several deep earthquakes providing rupture energy of six orders of magnitudes larger than the observable radiated seismic energy. This indicates that there might be space for redefining the commonly accepted order of magnitude for the seismic efficiency coefficient.Item Early european women In seismology(Earth Sciences History, 2024) Buforn Peiró, Vicenta María ElisaInge Lehmann is the best-known European woman seismologist, but she is not an isolated case. The presence of women seismologists in Europe has a long tradition, with the earliest women researchers appearing at the beginning of the 20th century in the United Kingdom, Denmark, the former USSR, and France. After World War II, women seismologists in Europe had an important presence. Their names are present in the lists of participants in seismological international meetings (IASPEI or ESC), where information about these women and their roles in these institutions can be found. This paper concentrates on the presence of women seismologists in Europe in the 1920–1970 period. After the 1970s, the number of women in seismology has increased considerably.Item Estudio estadístico de la dirección de esfuerzos principales en terremotos(2015) Buforn Peiró, Vicenta María ElisaItem The 2013 September-October seismic sequence offshore Spain: a case of seismicity triggered by gas injection?(Geophysical journal international, 2014) Cesca, Simone; Grigoli, Francesco; Heimann, Sebastian; Buforn Peiró, Vicenta María Elisa; Alvaro, González; Maghsoudi, Samira; Blanch, Estefania; Dahm, TorstenA spatially localized seismic sequence originated few tens of kilometres offshore the Mediterranean coast of Spain, close to the Ebro river delta, starting on 2013 September 5, and asting at least until 2013 October. The sequence culminated in a maximal moment magnitude Mw 4.3 earthquake, on 2013 October 1. The most relevant seismogenic feature in the area is the Fosa de Amposta fault system, which includes different strands mapped at different distances to the coast, with a general NE–SW orientation, roughly parallel to the coastline. However, no significant known historical seismicity has involved this fault system in the past. The epicentral region is also located near the offshore platform of the Castor project, where gas is conducted through a pipeline from mainland and where it was recently injected in a depleted oil reservoir, at about 2 km depth. We analyse the temporal evolution of the seismic sequence and use full waveform techniques to derive absolute and relative locations, estimate depths and focal mechanisms for the largest events in the sequence (with magnitude mbLg larger than 3), and compare them to a previous event (2012 April 8, mbLg 3.3) taking place in the same region prior to the gas injection. Moment tensor inversion results show that the overall seismicity in this sequence is characterized by oblique mechanisms with a normal fault component, with a 30◦ low-dip angle plane oriented NNE–SSW and a subvertical plane oriented NW–SE. The combined analysis of hypocentral location and focal mechanisms could indicate that the seismic sequence corresponds to rupture processes along shallow low-dip surfaces, which could have been triggered by the gas injection in the reservoir, and excludes the activation of the Amposta fault, as its known orientation is inconsistent with focal mechanism results. An alternative scenario includes the iterated triggering of a system of steep faults oriented NW–SE, which were identified by prior marine seismics investigations.Item A Threshold-Based Earthquake Early-Warning System for Offshore Events in Southern Iberia(Pure and applied geophysics, 2015) Picozzi, M; Colombelli, S; Carranza Gómez, Marta; Buforn Peiró, Vicenta María ElisaThe south of the Iberian Peninsula is a region situated at the convergence of the Eurasian and African plates. This region experiences large earthquakes with a long separation in time, the best known of which is the great 1755 Lisbon Earthquake (i.e., maximum macroseismic intensity, Imax=X), which occurred SW of San Vicente Cape (SW Iberian Peninsula). The high risk of damaging earthquakes has recently lead Carranza et al. (2013) to investigate the feasibility of an EEWS in this region. The analysis of the geometrical situation between the Iberian seismic networks and the San Vicente Cape area led the authors to conclude that a threshold-based approach, which would not require the real-time location of the earthquake, might be the best option for EEWS in SW Iberia. The current work explores this hypothesis, and proposes a new EEW approach that extends the standard P-wave threshold based single station analysis to the whole network. The proposed method allows the real-time estimation of the potential damage at stations that are triggered by P-waves, as well as at the not-triggered ones, giving the advantage of a greater lead-time for the release of alerts. Results of tests made with synthetic data mimicking the scenario of the great 1755 Lisbon Earthquake, and those obtained by applying the new approach to available recordings, indicate that an EEW estimation of the potential damage associated with an event in the San Vicente Cape area can be obtained for a very large portion of the Iberian Peninsula.Item Candy wrapper for the Earth's inner core(Scientific reports, 2013) Mattesini, Maurizio; Belonoshko, A.B.; Tkalčić, H.; Buforn Peiró, Vicenta María Elisa; Udías Vallina, Agustín; Ahuja, R.Recent global expansion of seismic data motivated a number of seismological studies of the Earth’s inner core that proposed the existence of increasingly complex structure and anisotropy. In the meantime, new hypotheses of dynamic mechanisms have been put forward to interpret seismological results. Here, the nature of hemispherical dichotomy and anisotropy is re-investigated by bridging the observations of PKP(bc-df) differential travel-times with the iron bcc/hcp elastic properties computed from first-principles methods.The Candy Wrapper velocity model introduced here accounts for a dynamic picture of the inner core (i.e., the eastward drift of material), where different iron crystal shapes can be stabilized at the two hemispheres. We show that seismological data are best explained by a rather complicated, mosaic-like, structure of the inner core, where well-separated patches of different iron crystals compose the anisotropic western hemispherical region, and a conglomerate of almost indistinguishable iron phases builds-up the weakly anisotropic eastern side.Item Intermediate-depth earthquakes in southern Spain and Alboran Sea(Tectonophysics, 2022) López Sánchez, Carolina; Buforn Peiró, Vicenta María Elisa; Cesca, Simone; Lozano, Lucía; Sanz de Galdeano, Carlos; Mattesini, Maurizio; Udías Vallina, Agustín; Cantavella, Juan VicenteA striking feature of the seismicity in the Ibero-Maghrebian region is a narrow band of intermediate-depth earthquakes (50 < h < 100 km) beneath the western part of the Alboran Sea, with epicenters following a NNE-SSW alignment. The origin and characteristics of this seismicity are debated, and an accurate analysis of this seismic scenario is provided despite the low to moderate magnitude of these earthquakes. In this study, we collect 20 years of seismic data from permanent and temporary installations and reprocess these data with the aid of advanced seismological techniques, including non-linear probabilistic relocation with a 3D-Earth velocity model and a probabilistic moment tensor inversion scheme, to shed new light on intermediate-depth seismicity in Southern Spain and the Alboran Sea. We relocated 238 intermediate-depth earthquakes (M >= 3) using a nonlinear probabilistic approach and a recent regional 3D tomography lithospheric velocity model for the Alboran-Betic Rif Zone. Maximum likelihood hypocenters confirm the NNE-SSW distribution in a depth range between 50 and 100 km, depicting three clusters of epicenters with a seismic gap that may be correlate to the boundary between the sunken slabs of the Iberian and African plates around Gibraltar. We simultaneously determined the focal mechanisms of 25 mb > 3.9 earthquakes using P-waves and moment tensors by fitting body-wave amplitude spectra and waveform cross-correlations. We performed an accurate resolution study by repeating the inversion using different 1-D velocity models. The results show predominant horizontal T axes with a rotation on the direction from NE-SW in southern Spain to E-W near the African coast. The distribution of intermediate-depth earthquakes and their source geometries provide new evidence of the seismotectonic complexity of the region, which is possibly controlled by the stopping or slowing down of subduction.Item Four Years of Earthquake Early Warning in Southern Iberia: 2016-2019(Frontiers in Earth Science, 2021) Carranza, Marta; Mattesini, Maurizio; Buforn Peiró, Vicenta María Elisa; Zollo, Aldo; Torrego, IreneThe performance of an earthquake early warning system (EEWS) for southern Iberia during the period of 2016-2019 is analyzed. The software PRESTo (PRobabilistic and Evolutionary early warning SysTem; the University of Naples Federico II, Italy) operating at the Universidad Complutense de Madrid has detected 728 events (2 < M-w < 6.3), with 680 earthquakes occurring in southern Iberia. Differences between the EEWS origin time and epicenter and those of the Instituto Geografico Nacional (IGN) catalog are less than 2 s and 20 km, respectively, for 70% of the detected earthquakes. The main differences correspond to the EEWS magnitude that is underestimated for earthquakes that occurred at the west of the Gibraltar Strait (M-w differences larger than 0.3 for 70%). To solve this problem, several relationships have been tested, and a modification to those that currently use PRESTo is proposed. Other improvements, such as to densify the network or to use 3D Earth models, are proposed to decrease the time needed to issue the alert and avoid the false alerts (19 events over a total of 728 events). The EEWS has estimated the depth for 680 events and compared to those from the IGN (491 events). The performance of PRESTo during the 2020-2021 Granada swarm is analyzed. The hypocentral locations for the three largest earthquakes are close to those from the IGN (differences from 1 to 7 km for the epicenter and 0 s for the time origin), although there are some differences in their magnitude estimations that varies from 0.2 to 0.5. The PRESTo first times are 17, 25, and 41 s after the origin time. This study shows that the actual PRESTo EEWS configured for the southern Iberia may generate effective warnings despite the low seismicity rate in this region. To decrease the warning time, the geometry and density of the seismic network must be improved together with the use of 3D Earth models and on-site system approaches.