Browsing by Author "Gonzalez, J."

Now showing 1 - 7 of 7
  • No Thumbnail Available
    Item
    A probabilistic seismic hazard assessment of southern Peru and Northern Chile
    (2020) Das, Ranjit; Gonzalez, G.; Llera Martin, Juan Carlos de la; Sáez Robert, Esteban; Salazar, P.; Gonzalez, J.; Meneses, C.
    Southern Peru and northern Chile (17–30°S, 67–74°W) make up a seismically active region due to the convergence of the Nazca Plate and the South American Plate. The region has experienced a number of destructive earthquakes and tsunamis over the past few centuries, which have caused loss of human life and significant damage to infrastructure, highlighting the importance of seismic hazard assessment in the region. In fact, a reliable seismic hazard assessment is critical for developing policies for seismic hazard mitigation and risk reduction. In this study, we performed a probabilistic seismic hazard assessment (PSHA) of the study area based on an earthquake catalog that was very carefully analyzed. In earlier studies, we demonstrated that inappropriate treatment of the earthquake catalog can result in a serious bias in evaluations of seismicity parameters (e.g., a bias of up to 42% in the “b” parameter of the Gutenberg–Richter law). To address this issue, we compiled a homogenous earthquake catalog consisting of 39,977 events during the 1513–2016 period and accounted for site-specific local effects by developing site-specific scaling relationships between different measures of magnitude (e.g., mb, Ms, MD) and moment magnitude (Mw). The study area was subdivided into 15 seismogenic zones, accounting for site-specific seismicity patterns. The parameters “a” and “b” of the Gutenberg–Richter law were estimated for each zone based on independent earthquake events. The PSHA was performed using a standard logic tree approach, which allowed us to systematically take into account the model-based uncertainty and its influence on the estimated ground motion parameters. Uniform hazard spectra for return periods of 475 and 2475 years were estimated for peak ground accelerations and spectral accelerations at 0.2 s and 1.0 s to meet the definitions of seismic hazards provided by the International Building Code (IBC, International Code Council [ICC], 2009). This study is expected to provide a basis for design maps for building codes and emergency planning.
  • Thumbnail Image
    Item
    Behaviour of a copper-AISI 304 stainless steel mixed anode in electrolytic copper refining with periodic current reversal
    (1986) Rojo, A.; Gonzalez, J.
    In the search for suitable materials to be used as anode supports in the periodic current reversal refining process this work covers the study of austenitic AISI 304 stainless steel. Experimental results show that the resistance of this steel to the aggressive action of the refining electrolyte is good at the working temperature of 60 C since no corrosion was detected after 24 h of electrolysis. The periodic polarization of this material results in a progressive passivation which was observed by operating under different initial surface conditions and by detecting remnant anodic currents which gradually decreased with time. For time ratios lower than twenty, a build up of metallic copper deposit on the steel part of the mixed anode occurred whatever the current density used.
  • No Thumbnail Available
    Item
    Critical role of histidines 120, 213, 245 and 319 for the potentiation of the P2X(2) receptor by copper or zinc
    (2004) Huidobro-Toro, J.P.; Lorca Rojas, Ramón Alberto; Bull Simpfendorfer, Paulina; Bravo, L.; Arredondo, C.; Gonzalez, J.; Leiva Llantén, Eduardo David
  • Thumbnail Image
    Item
    Erratum to: Two teacher quality measures and the role of context: evidence from Chile
    (2017) Santelices Etchegaray, María Verónica; Valencia, E.; Gonzalez, J.; Taut, Marianne Sandy
  • Thumbnail Image
    Item
    Exercise and prostate cancer : from basic science to clinical applications
    (2018) Campos, C.; Sotomayor, P.; Jerez, D.; Gonzalez, J.; Schmidt, C.; Schmidt, K.; Banzer, W.; Godoy, Alejandro S.
  • Thumbnail Image
    Item
    Formation of camosine-Cu(II) complexes prevents and reverts the inhibitory action of copper in P2X(4) and P2X(7) receptors
    (2002) Coddou Álvarez, Claudio; Villalobos, C.; Gonzalez, J.; Acuna-Castillo, C.; Loeb Luschow, Bárbara; Huidobro-Toro, J.P.
  • Thumbnail Image
    Item
    The central engine of GRB 130831A and the energy breakdown of a relativistic explosion
    (OXFORD UNIV PRESS, 2016) De Pasquale, M.; Oates, S. R.; Racusin, J. L.; Kann, D. A.; Zhang, B.; Pozanenko, A.; Volnova, A. A.; Trotter, A.; Frank, N.; Cucchiara, A.; Troja, E.; Sbarufatti, B.; Butler, N. R.; Schulze, S.; Cano, Z.; Page, M. J.; Castro Tirado, A. J.; Gorosabel, J.; Lien, A.; Fox, O.; Littlejohns, O.; Bloom, J. S.; Prochaska, J. X.; de Diego, J. A.; Gonzalez, J.; Richer, M. G.; Roman Zuniga, C.; Watson, A. M.; Gehrels, N.; Moseley, H.; Kutyrev, A.; Zane, S.; Hoette, V.; Russell, R. R.; Rumyantsev, V.; Klunko, E.; Burkhonov, O.; Breeveld, A. A.; Reichart, D. E.; Haislip, J. B.
    Gamma-ray bursts (GRBs) are the most luminous explosions in the Universe, yet the nature and physical properties of their energy sources are far from understood. Very important clues, however, can be inferred by studying the afterglows of these events. We present optical and X-ray observations of GRB 130831A obtained by Swift, Chandra, Skynet, Reionization And Transients Infra-Red camera, Maidanak, International Scientific Optical-Observation Network, Nordic Optical Telescope, Liverpool Telescope and Gran Telescopio Canarias. This burst shows a steep drop in the X-ray light curve at similar to 10(5) s after the trigger, with a power-law decay index of a similar to 6. Such a rare behaviour cannot be explained by the standard forward shock (FS) model and indicates that the emission, up to the fast decay at 105 s, must be of 'internal origin', produced by a dissipation process within an ultrarelativistic outflow. We propose that the source of such an outflow, which must produce the X-ray flux for similar to 1 d in the cosmological rest frame, is a newly born magnetar or black hole. After the drop, the faint X-ray afterglow continues with a much shallower decay. The optical emission, on the other hand, shows no break across the X-ray steep decrease, and the late-time decays of both the X-ray and optical are consistent. Using both the X-ray and optical data, we show that the emission after similar to 10(5) s can be explained well by the FS model. We model our data to derive the kinetic energy of the ejecta and thus measure the efficiency of the central engine of a GRB with emission of internal origin visible for a long time. Furthermore, we break down the energy budget of this GRB into the prompt emission, the late internal dissipation, the kinetic energy of the relativistic ejecta, and compare it with the energy of the associated supernova, SN 2013 fu.