Location
San Diego, California
Presentation Date
30 Mar 2001, 1:30 pm - 3:30 pm
Abstract
We present two new techniques for treating earthquake intensity data objectively and reproducibly. First, our natural-neighbor, n-n, isoseismals (program: ConVor) are used to draw objective and reproducible isoseismals of the Whittier Narrows ML=5.9, 1987 earthquake from the earthquake damage (“felt reports”) sparsely observed in the region by the U.S.G.S. ConVor uses the n-n coordinates to weight and interpolate the observations; thus, the weights of the experimental sites which are natural neighbors to a new point are proportional to the areas of the intersections of their Voronoi polygons. It is shown that the n-n isoseismals: 1) honour the experimental data completely, and are, thus, frequency-complete representations; 2) are easy-to-grasp and reliable overviews of regional earthquake damage; 3) do not ballast any subsequent quantitative treatment, because they do not introduce new (contouring) parameters. Secondly, we demonstrate that the approximate source geometry and kinematics of this earthquake can be back-predicted by inverting its intensity data automatically. The inversion involves twelve parameters, the most sensitive of which are the epicentral co-ordinates and the fault plane solution; our trial-and-error technique minimizes the sum of the squared residuals (calculated intensity - minus - observed intensity) at the surveyed sites, and the errors of the source parameters are also estimated.
Department(s)
Civil, Architectural and Environmental Engineering
Meeting Name
4th International Conference on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Publisher
University of Missouri--Rolla
Document Version
Final Version
Rights
© 2001 University of Missouri--Rolla, All rights reserved.
Creative Commons Licensing
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Document Type
Article - Conference proceedings
File Type
text
Language
English
Recommended Citation
Pettenati, Franco and Sirovich, Livio, "New-Generation Objective and Reproducible Isoseismals, and Tests of Source Inversion of the USGS "Felt Reports"" (2001). International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics. 6.
https://scholarsmine.mst.edu/icrageesd/04icrageesd/session03/6
Included in
New-Generation Objective and Reproducible Isoseismals, and Tests of Source Inversion of the USGS "Felt Reports"
San Diego, California
We present two new techniques for treating earthquake intensity data objectively and reproducibly. First, our natural-neighbor, n-n, isoseismals (program: ConVor) are used to draw objective and reproducible isoseismals of the Whittier Narrows ML=5.9, 1987 earthquake from the earthquake damage (“felt reports”) sparsely observed in the region by the U.S.G.S. ConVor uses the n-n coordinates to weight and interpolate the observations; thus, the weights of the experimental sites which are natural neighbors to a new point are proportional to the areas of the intersections of their Voronoi polygons. It is shown that the n-n isoseismals: 1) honour the experimental data completely, and are, thus, frequency-complete representations; 2) are easy-to-grasp and reliable overviews of regional earthquake damage; 3) do not ballast any subsequent quantitative treatment, because they do not introduce new (contouring) parameters. Secondly, we demonstrate that the approximate source geometry and kinematics of this earthquake can be back-predicted by inverting its intensity data automatically. The inversion involves twelve parameters, the most sensitive of which are the epicentral co-ordinates and the fault plane solution; our trial-and-error technique minimizes the sum of the squared residuals (calculated intensity - minus - observed intensity) at the surveyed sites, and the errors of the source parameters are also estimated.
