Fig 4 - uploaded by Zenon Aguilar
Content may be subject to copyright.
Source publication
The estimation of the shear-wave velocity profile in Lima, Peru, was originally performed through surface wave observation in microtremor arrays. In the observation of these surface waves, a low signal problem for long periods was identified that resulted in a poorly done correlation between signals recorded by sensors and, consequently, in difficu...
Context in source publication
Context 1
... earthquakes were considered in the analysis, one on August 24, 2011 (M W 7.0) and one on October 28, 2011 (M W 6.8). The locations of these earthquake epicenters are shown in Fig. 4. As can be seen in Fig. 5, the October 28 earthquake was recorded by the four seismometers but the August 24 earthquake was recorded by only three. This figure also shows the direction of the earthquake epicenter. ...
Similar publications
Recordings of weak-motion S waves at two deep vertical seismic arrays in the northern Mississippi embayment (i.e., vertical seismic array Paducah [VSAP] and the Central United States Seismic Observatory [CUSSO]) were used to estimate empirical site responses using ratios of surface-to-bedrock transverse-component amplitude spectra TFT. The mean TFT...
Citations
... The values of T were obtained from HV spectral ratio of seismic records (HV spectrum) and the values of Vs obtained from surface waves measurements tests of the first 30 m depth (Vs 30 ) and the inversion of the HV spectrum, as mentioned by Soto (2021) and Soto & Alva (2022). The values obtained for deep Vs profile are similar to those obtained by Calderon et al (2013). ...
... Since Peru is located along the Nazca Plate zone, and has been affected by large earthquakes such as the 2007 Pisco earthquake, Lima has been also anticipated to be attacked by a large earthquake in near future. In order to estimate Vs profiles and assess the SAFs in Lima, multichannel analysis of surface waves (MASW) method and microtremor array measurements have been conducted at many sites [2][3][4][5]. Deep Vs profile to seismic bedrock is needed for accurately evaluating SAFs. However, the number of sites where such deep profile was obtained from the measurements is still limited. ...
Evaluation of site amplification factors (SAFs) of seismic waves has been one of the important issues for evaluating seismic hazards. The authors have proposed a deep neural network (DNN) model in order to cost-effectively and accurately estimate SAF from microtremor horizontal-to-vertical spectral ratio (MHVR). In this study, we assessed the SAFs in southern Lima, Peru by estimating from MHVRs and DNN. First, we validated the applicability of the DNN model to Lima by estimating the SAFs from the MHVRs observed at seismic stations in Lima. From the comparison with the observed SAFs derived from spectral inversion technique, we confirmed that the SAFs in Lima were accurately estimated by the DNN model. The SAFs in the southern Lima including Chorrillos and Villa El Salvador districts were evaluated by applying the DNN model to the observed MHVRs at approximately 250 sites. We found that large amplifications at low frequency around 1 Hz were expected in the southeastern coastal areas formed by eolian sands whereas smaller amplification were estimated in the northwestern areas mainly located on alluvial deposits.
... Group 1 studies seismic motion and geotechnical aspects through seismic and microtremor observations at the case study sites. Together with existing geological data and newly conducted borehole surveys, the soil amplification characteristics have been investigated [5][6][7]. ...
... Group 1 studies seismic motion and geotechnical aspects through seismic and microtremor observations at the case study sites. Together with existing geological data and newly conducted borehole surveys, the soil amplification characteristics have been investigated [5][6][7]. ...
One of the SATREPS projects on earthquake and tsunami disaster mitigation technology in Peru has been promoted since March 2010 for a five-year period. The project focuses on five research fields, i.e., seismic motion and geotechnical, tsunamis, buildings, damage assessment, and disaster mitigation planning. Collaborative research has been carried out through joint experiments, observations, field surveys, computer simulations, seminars and workshops. With the Lima metropolitan area and the city of Tacna set as case study sites, two mega-thrust earthquakes have been simulated and their effects and countermeasures investigated. The simulation results have been validated by observation data and have been implemented in government policy. Young Peruvian engineers and scientists have also received training and education. This paper summarizes the progress and outcomes of the SATREPS project for earthquake and tsunami disaster mitigation in Peru.
... In previous studies [10,11], the efficiency of the use of shear wave velocity profiles in Lima as a tool to adequately characterize the seismic response was demonstrated. The change in the dynamic properties of the soil can give us a clue to any difference in the response of the soil under the effect of strong motions. ...
During the last fifty years, the city of Lima has experienced an immigration process that has led to the urbanization of the Andean foothills surrounding the capital. With the aim of analyzing the dynamic response of these new populated places, a target area in a district called Independencia is chosen. Seven microtremor array measurements are carried out at different points on the flat level and along the slope in order to evaluate the variation in the depth of the bedrock. In addition, a seismometer is installed on the slope with the objective of determining if amplification due to topography exists in the area of study.
The 2011 moment magnitude (M w) 9.0 Tohoku-Oki Japan earthquake occurred in a region where giant megathrust earthquakes were not expected. This earthquake proved the difficulty in assessing seismic hazard by relying mainly on information from historical and instrumental seismicity. To help improve the seis-mic-hazard assessment for such rare events, we propose a methodology to estimate the slip distribution of future megathrust earthquakes based on a model of interseismic coupling distribution in subduction margins, as well as information of historical earth-quakes, and apply the method to the central Peru region, Lima. The slip model ob-tained from geodetic data represents the large scale features of asperities within the megathrust, which is appropriate for simulation of long-period waves and tsunami modeling. For the simulation of a broadband strong ground motion, we add small scale heterogeneities to the source slip to be able to simulate high frequencies. To achieve this purpose, we propose broadband source models constructed by adding short-wavelength slip distributions obtained from a Von Karman power spectral den-sity function, to the slip model inferred from interseismic geodetic data. Using these slip models and assuming several hypocenter locations, we calculate a set of strong ground motions for Lima and incorporate site effects obtained from microtremors sur-veys and geotechnical data. Our simulated average pseudospectral accelerations (period 0.3 s) are above 1:5g for wide areas in Lima, which may be critical in terms of damage of low-to midrise masonry and reinforced concrete buildings, which char-acterize the majority of buildings in Lima.
