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Accession Number:

AD1084861

Title:

Calibration of Seismic Location in Central Andes of Bolivia

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Report Date:

2019-06-07

Abstract:

The Central Andes is a high plateau with elevations above 3400 m., the crustal thickness and shortening process due to the subduction between the Nazca and South America plates, the seismicity along the Central Andes is distributed by sources, the crustal shallow seismicity is related to natural crust deformation, especially on the Bolivian Orocline (from ), depths are distributed from 5 to 70 km. Subduction processes have two sources, intermediate from 100 to 350 km depth and deeper from 500 to 650 km. Furthermore far away seismicity also affects the Central Andes. Locating earthquakes in the region is always difficult, with a lot of uncertainty due to Moho variations along the Central Andes. Further there was not enough data to perform tomography to resolve the problem. After 2016 a 1D velocity model based on the previous research on receiver functions in the Central Andes was proposed and the results showed more coherency and accuracy also with international agencies. Different location algorithms were tested with our 1D velocity model which showed better performance, especially when we applied iLOC 3D locating software. Once earthquakes were accurate located, we proposed to obtain focal mechanism solutions to enhance the knowledge of seismicity for the Central Andes. The method applied was the double couple with first polarities of waveforms. Each result has at least one plane coherent with the geologic context. Furthermore with the data already processed a Moment Tensor Inversion was calculated for three seismic events, those events showed coherent results that helped us to understand the fault procedure.

Pages:

58

File Size:

8.25MB

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Distribution Statement:

Approved For Public Release

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