Site Characterization by Means of Geophysical MASW Method at Designated Instrumented Sites of the Puerto Rico Strong Motion Program Seismic Network
Description:
In the seismological and engineering community the influence of the local site effects are of special interest in obtaining reliable seismic records. Local site effects are associated on the records with the amplitude, duration, and frequency content of the seismic records and directly related to the morphological and mechanical properties of the ground, aimed at describing their effects on seismic ground motion for applications related to ground-motion studies and engineering seismology.
During the Fall of 2021, the working group of the Puerto Rico Strong Motion Program (PRSMP), conducted a Multichannel Analysis of Surface Waves (MASW) field work on eleven designated permanent sites instrumented with accelerometers of the PRSMP.
Active and Passive MASW measurements were taken in 24 geophones array spaced three meters each. For the active source mode (Active MASW), shots were hit with a 16lb sledge hammer at offsets of ±1.5m, ±3.0m, ±9.0m, ±21m, at both ends of the array and at 11 selected sites among the geophones. The ambient vibration measurements (Passive MASW) lasted up to one hour of record length.
The collected time series were processed to obtain the dispersion curves for the afterward inversion process in obtaining the site conditions in terms of the 2D VS-Z profile. Preliminary results of the 2D VS-Z profiles of this on-going research of the studied sites and their site/soil classification according to NEHRP range from soil type D (Site UTD2,) and C for the majority of the sites. At the site FJR1, the shear wave velocity of its structure shallow portion averaged 450 m/s, and at the depth of 18 m the estimated shear wave velocity reached 920 m/s, however in terms of NEHERP VS30 the soil type classification still on the category of soil type C.
Session: From Sensors and Networks to Site Characterization and Site Response: Coming Full Circle
Type: Oral
Date: 4/18/2023
Presentation Time: 10:00 AM (local time)
Presenting Author: Carlos I. Huerta-López
Student Presenter: No
Invited Presentation: Yes
Authors
Carlos Huerta-López Presenting Author Corresponding Author carlos.huerta@upr.edu University of Puerto Rico, Mayagüez |
Germán Herrera-Laverde german.herrera@upr.edu University of Puerto Rico |
Jerson López-Fajardo jerson.lopez@upr.edu University of Puerto Rico |
Manuel Rodríguez-Jiménez miguel.rodriguez40@upr.edu University of Puerto Rico |
José Martínez-Cruzado jamc2861@gmail.com University of Puerto Rico |
Luis Suárez-Colche luis.suarez3@upr.edu University of Puerto Rico |
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Site Characterization by Means of Geophysical MASW Method at Designated Instrumented Sites of the Puerto Rico Strong Motion Program Seismic Network
Category
From Sensors and Networks to Site Characterization and Site Response: Coming Full Circle