CSDMS 2024: Coastlines, Critical Zones and Cascading Hazards: Modeling Dynamic Interfaces from Deep Time to Human Time

New features and basic usage of the GeoClaw software for depth-averaged flow

Randy LeVeque

University of Washington, United States
Marsha Berger NYU United States
Kyle Mandli Flatirons Institute United States

GeoClaw ( is an open-source software package for solving two-dimensional depth-averaged equations over general topography using high-resolution finite volume methods and adaptive mesh refinement. Wetting-and-drying algorithms allow modeling inundation and overland flows. The primary applications where GeoClaw has been used are tsunami modeling and storm surge, although it has also been applied to dam break and other overland flooding problems.

The first part of this clinic will present an overview of the capabilities of GeoClaw, including a number of new features have been added in the past few years. These include:

- Depth-averaged Boussinesq-type dispersive equations that better model short-wavelength tsunamis, such as those generated by landslides or asteroid impacts. Solving these equations requires implicit solvers (due to the higher-order derivatives in the equations).  This is now working with the adaptive mesh refinement (AMR) algorithms in GeoClaw, which are critical for problems that require high-resolution coastal modeling while also modeling trans-oceanic propagation, for example.

- Better capabilities for extracting output at frequent times on a fixed spatial grid by interpolation from the AMR grids during a computation. The resulting output can then be use for making high-resolution animations or for post-processing (e.g. the velocity field at frequent times can be used for particle tracking, as needed when tracking tsunami debris, for example).

- Ways to incorporate river flows or tidal currents into GeoClaw simulation.
- Better coupling with the D-Claw code for modeling debris flows, landslides, lahars, and landslide-generated tsunamis. (D-Claw is primarily developed by USGS researchers Dave George and Katy Barnhart).

The second part of the clinic will be a hands-on introduction to installing GeoClaw and running some of the examples included in the distribution, with tips on how best to get started on a new project.

GeoClaw is distributed as part of Clawpack (, and is available via the CSDMS model repository. For those who wish to install the software in advance on laptops, please see We will also go through this briefly and help with any issues that arise on your laptop (provided it is a Mac or Linux machine; we do not support Windows.) You may need to install some prerequisites in advance, such as Xcode on a Mac (since we require "make" and other command line tools), a Fortran compiler such as gfortran, and basic scientific Python tools such as NumPy and Matplotlib. See

Please acknowledge the original contributors when you are using this material. If there are any copyright issues, please let us know ( and we will respond as soon as possible.

Of interest for:
  • Marine Working Group
  • Terrestrial Working Group
  • Coastal Working Group
  • Education and Knowledge Transfer (EKT) Working Group
  • Cyberinformatics and Numerics Working Group
  • Hydrology Focus Research Group
  • Chesapeake Focus Research Group
  • Critical Zone Focus Research Group
  • Human Dimensions Focus Research Group
  • Geodynamics Focus Research Group
  • Ecosystem Dynamics Focus Research Group
  • Coastal Vulnerability Initiative
  • Continental Margin Initiative
  • Artificial Intelligence & Machine Learning Initiative
  • Modeling Platform Interoperability Initiative
  • River Network Modeling Initiative