CENTRAL UNITED STATES VELOCITY MODEL VERSION 1: DESCRIPTION AND VALIDATION

Leonardo Ramirez-Guzman, Robert A. Williams, Oliver Boyd and Stephen Hartzell (USGS).

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A PIECE OF THE PUZZLE

Project: Earthquake simulations in the New Madrid Seismic Zone: The 1811–1812 Bicentennial.

Continious representationDiscretized representation

(etree)

Source definitionDeterministic and

Probablistic

1Hz (FEM HERCULES) 1D LAYERED STRUCTURE

Conceptual framework similar to those already done for 1906 and 1868 Hayward (Bay Area) and Shakeout (Southern CA) scenarios.

Input

Solver

Model Extension

Topographic map showing the extension of the CUSVM and earthquakes greater than magnitude 2.5 (red circles) that occurred after 1972.

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Model Overview. The white lines delineate the boundaries between the oldest units. The colormap indicates the Vs (m/s) distribution.

Moho

Precambrian Unconformity

Upper Mantle

TN

IL

MO

IN

KY

ARAL

Lower Crust

Upper Crust (ENA Model)

VELOCITY MODEL

Modified Lower

Crust

Vs(m

/s)

4

Vs(m/s)

SHALLOW STRUCTURE

0 500 1000 1500 2000

Shallow structure. Velocity and topography. The colormap indicates the Vs (m/s) distribution.

St. Louis Arch

St. Louis

Memphis

St. Louis area

Memphisarea

Latit

ude

Latit

ude

Latitude