Browsing by Author "Montalva, Gonzalo"

Now showing 1 - 7 of 7
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    Dynamic site characterization of areas affected by the 2017 Puebla-Mexico city earthquake
    (2019) Wood, Clinton M.; Deschenes, Michael; Ledezma Araya, Christian Alfonso; Meneses, Jorge; Montalva, Gonzalo; Morales Vélez, Alesandra C.
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    Effects of Ground Failure on Buildings, Ports, and Industrial Facilities
    (EARTHQUAKE ENGINEERING RESEARCH INST, 2012) Bray, Jonathan; Rollins, Kyle; Hutchinson, Tara; Verdugo, Ramon; Ledezma, Christian; Mylonakis, George; Assimaki, Dominic; Montalva, Gonzalo; Arduino, Pedro; Olson, Scott M.; Kayen, Robert; Hashash, Youssef M. A.; Candia, Gabriel
    Soil liquefaction occurred at many sites during the 2010 Maule, Chile, earth-quake, often leading to ground failure and lateral spreading. Of particular interest are the effects of liquefaction on built infrastructure. Several buildings were damaged significantly due to foundation movements resulting from liquefaction. Liquefaction-induced ground failure also displaced and distorted waterfront structures, which adversely impacted the operation of some of Chile's key port facilities. Important case histories that document the effects of ground failure on buildings, ports, and industrial facilities are presented in this paper. [DOI: 10.1193/1.4000034]
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    Geological and geotechnical investigation of the seismic ground response characteristics in some urban and suburban sites in Chile exposed to large seismic threats
    (2022) Maringue, Jose; Mendoza, Laura; Saez, Esteban; Yanez, Gonzalo; Montalva, Gonzalo; Soto, Valeria; Ayala, Felipe; Perez-Estay, Nicolas; Figueroa, Ronny; Sepulveda, Natalia; Galvez, Carlos; Ramirez, Paola; Ovalle, Carlos
    The central area of Chile's Valparaiso Region has been classified as a seismic gap for a major earthquake, which makes it very important to understand the seismic hazard of the zone. Generally, seismic codes consider a qualitative classification of sites to estimate the possible damage in the case of an earthquake scenario. Estimating the values of acceleration could be very important to prevent damages and increase preparedness for these rare events. In this research, a qualitative and quantitative estimation of seismic hazard is performed in the study area (Valparaiso region between Papudo and San Antonio 32 degrees-34 degrees S). This is achieved through an integrated and relatively economical approach which considers the information from Geology, Geophysical experiments (Gravity and seismic methods), and Geotechnical analyses. The results of the geophysical survey and geology information allow dividing the zone into five site types through a new proposal of site classification that depends not only on the V-s30,V- but also on the sites predominant period (T-0), which is an innovation of this work for the Chilean code. The Peak Ground Acceleration (PGA) values in the study zone were estimated using a Ground Motion Predictive Equation developed for the Chilean subduction zone. Additionally, we consider three different seismic scenarios according to the history of events in Central Chile. The results of this quantitative analysis show PGA values up to 0.52 g for the median and 1.2 g for the 84th percentile of the scenarios. Overall, the highest accelerations (PGA) are in zones with low shear wave velocities (< 500 m/s), a long predominant period (> 0.4 s) and where geology establishes the presence of low stiffness soils. The comparison of response spectra from the model against records from 2010 Maule and 1985 Valparaiso earthquakes shows available models tend to overpredict the intensities.
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    Geophysical Characterization of the Chilean Seismological Stations : First Results
    (2018) Leyton, Felipe; Leopold, Alexander; Hurtado, G.; Pasten, Cesar; Ruiz, Sergio; Montalva, Gonzalo; Sáez Robert, Esteban
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    Geotechnical Aspects of the 2015 Mw 8.3 Illapel Megathrust Earthquake Sequence in Chile
    (2017) Candia, Gabriel; De Pascale, Gregory P.; Montalva, Gonzalo; Ledezma Araya, Christian Alfonso
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    InSAR Monitoring Using Persistent Scatterer Interferometry (PSI) and Small Baseline Subset (SBAS) Techniques for Ground Deformation Measurement in Metropolitan Area of Concepción, Chile
    (2023) Giorgini, Eugenia; Orellana, Felipe; Arratia, Camila; Tavasci, Luca; Montalva, Gonzalo; Moreno, Marcos; Gandolfi, Stefano
    InSAR capabilities allow us to understand ground deformations in large metropolitan areas, this is key to assessing site conditions in areas in an inherently expanding context. The multi-temporal interferometry of SAR data records ground surface displacement velocities over large metropolitan areas, identifying anomalous and potential geological hazards. The metropolitan city of Concepcion, Chile, is an alluvial basin in one of the world's most seismically active subduction zones, where many subduction earthquakes have occurred throughout history. In this study, we monitored the deformations of the ground surface in the metropolitan area of Concepcion using two interferometric techniques, the first being Persistent Scatterer Interferometry (PSI) and the second, the Small Baseline Subset (SBAS) technique. To do this, we have used the same Sentinel-1 dataset, obtaining ground movement rates between 2019 and 2021. The velocities were aligned with the GNSS station available in the area. Ground deformation patterns show local deformations depending on factors such as soil type and heterogeneity, and regional deformations due to geographical location in the subduction area. Our results highlight the similarity of the deformation rates obtained with different processing techniques and have also allowed us to identify areas of deformation and compare them to site conditions. These results are essential to evaluate ground conditions and contribute to urban planning and risk management in highly seismic areas.
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    Two-dimensional nonlinear dynamic analysis of a liquefaction case history considering spatial variability and long-duration megathrust earthquakes
    (2024) Saldana-Sotelo, Hector; Montalva, Gonzalo; Escribano, Daniella; Nunez-Jara, Sebastian; Tiznado, Juan Carlos
    We analyzed the unusual liquefaction response of the Los Presidentes site in Concepci ' on, Chile, during the 2010 Mw 8.8 Maule earthquake, using a series of twodimensional nonlinear dynamic analyses (NDAs) on a well characterized subsurface. This site, characterized by interbedded clean and silty sands followed by a dense sand unit, included four identical towers that experienced different settlements, with maximum values reaching 40 cm for the most damaged tower to zero for the less affected one. We used SPT, CPTu, and Vs tests to characterize the soil's spatial variability. The NDAs used the PM4Sand and PM4Silt soil constitutive models implemented in OpenSees. The results suggest that the shear-induced deformation mechanism controls the dynamic response. The computed settlements matched post-earthquake LiDAR and field measurements, while liquefaction vulnerability indexes underestimated observed manifestations. Our results show that liquefactioninduced settlements due to megathrust earthquakes greatly differ from those induced by crustal ground motions.