Southern California Seismic Velocity Model Vertical Profiles

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Best Southern California Velocity Models

Modifying the Geotechnical Layer

Kim Olsen's group has publish papers on how to modify the CVM-S4.26.M01 near surface properties to get a better fit to recorded ground motion records.

My group just published two companion papers in GJI:,

One the study finds that a 700-1,000 m tapered GTL produces better results than a 350 m GTL for La Habra. The other paper is derived from his High-f efforts, a 0-5 Hz study on La Habra, where we quantify the effects on ground motions from topography, Q(f), and GTL using a source that Rob generated long time ago. Here, he advocates for a Qs=(0.075,1.0)Vs model. The papers were part of Kim's student Zhifeng Hu's PhD thesis.

Options for Generating Vertical Profiles

  1. UCVM Website
  2. UCVM plot vertical profile
  3. UCVM ucvm_query

UCVM Website (prototype)

All the currently available velocity models are registered into this webviewer. Select a velocity model of interest using the dropdown menu.

A menu selection asks if you want to query the model by elevation or by depth. Default for CVM-S4, CVM-S4.26, and CVM-S4.26.M01 are positive numbers below earth surface. If you query by elevation steps are positive above Mean Sea Level, and negative downward.

Converting UCVM Vertical profile Metadata

Both the UCVM website and ucvm plotting create png plots, and metadata files with the data being plotted. The metadata files can be difficult to interpret. SCEC has a Python3 script that combines.

Accessing Docker Images

Docker is a software system that enables users to run Linux software on Mac, Windows, and Linux systems. Science applications are distributed as "Docker Images" which include all the required software including the Operating system, compilers, and science software. Docker Images can be run using a free software called a Docker Client. Docker Client software is available for Mac, Windows, and Linux systems, and be downloaded for free from Docker:

Docker has largely replace "Virtual Box" technology which was used in the past to run Linux software on Mac and other systems.

Docker Client software:

SCEC Community Fault Model w/ Hauksson Catalog

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