GeoClaw

Warning

As with all of Clawpack, this code is provided as a research and teaching tool with no guarantee of suitability for any particular purpose, and no liability on the part of the authors. See the License for more details and Cautionary Hints on using GeoClaw for tips on exercising appropriate care in using the code.

Note: Several improvements to GeoClaw are still under development and should appear in Clawpack 5.1.

See also:

• Cautionary Hints on using GeoClaw

• Topography data

• Specifying GeoClaw parameters in setrun.py

• Plotting routines for GeoClaw

• Quick start guide for tsunami modeling

• Earthquake sources: Fault slip and the Okada model

• Setting sealevel

• Manning friction term

• Some sources of tsunami data

• Links to relevant papers and sample codes based on the Clawpack 4.x version of GeoClaw.

Overview

The $CLAW/geoclaw directory contains a specialized version of some Clawpack and AMRClaw routines that have been modified to work well for certain geophysical flow problems.

Currently the focus is on 2d depth-averaged shallow water equations for flow over varying topography. The term bathymetry is often used for underwater topography (sea floor or lake bottom), but in this documentation and in the code the term topography is often used to refer to either.

A primary concern with such flows is handling the margins of the flow where the depth goes to 0, for example at the shore line. In GeoClaw this is handled by letting the depth variable h in the shallow water equations be 0 in some cells. Robust Riemann solvers are used that allow for dry cells adjacent to wet cells and that allow wetting and drying, for example as a tsunami inundates dry land.

Some sample calculations can be viewed in the gallery_geoclaw. More will eventually appear in the Clawpack Applications repository.

Running a GeoClaw code

Setting up, running, and plotting a GeoClaw application follows the same pattern as other AMRClaw applications, which in turn use many of the same conventions as the classic single grid Clawpack code, in particular:

• Setting parameters is done in setrun.py, as for other versions of Clawpack, as described in Specifying classic run-time parameters in setrun.py. However, there are several new parameters that may or must be set for GeoClaw. See Specifying GeoClaw parameters in setrun.py for more details on these.

• The program can be compiled and run using make and make .output as for other versions, see Fortran version.

• Plots of results can be created either as a set of webpages via make .plots or interactively using Iplotclaw. See Visclaw Plotting options for more details. Some additional Python plotting tools that are useful for GeoClaw output (e.g. plotting land and water with different colormaps) are described in the section Plotting routines for GeoClaw.

Topography

To simulate flow over topography it is of course necessary to specify the topography. This is usually done by providing one or more files of surface elevation (relative to some reference, e.g. sea level) at a set of points on a rectangular grid (with x-y locations in Cartesian units or in latitude-longitude, depending on the application).

Several file formats are recognized by GeoClaw. See Topography data for more information on how to specify topography and some on-line resources for obtaining topography.

Plotting GeoClaw results

GeoClaw results can be plotted with the usual Python plotting tools (see Visclaw Plotting options).

Some special tools and colormaps are available, see GeoClaw plotting tools.

Setting up a new example

• Quick start guide for tsunami modeling