MondaicThis documentation is not for the latest stable Salvus version.
The effects of free-surface topography on seismic waveforms are significant, and any local study considering higher-frequency data must take topography into account. In this tutorial we'll explore how to add realistic free-surface topography to a
SimulationConfiguration object, and investigate how high-order accurate topography / material interpolation can be used to improve simulation performance. To accomplish this, we'll focus on a real-life use case using the area around Mt. St. Helens in Washington state as an example. Of course please feel free to adapt the geographical area.As always, we'll start by importing the Salvus namespace.
%matplotlib inline
import os
import pathlib
import salvus.namespace as sn# This notebook will use this variable to determine which
# remote site to run on.
SALVUS_FLOW_SITE_NAME = os.environ.get("SITE_NAME", "local")
PROJECT_DIR = "project"There are a number of ways topography can be specified in Salvus. In addition it has two built-in ways to acquire real world digital elevation data at fairly high resolution:
We focus on the first approach for the purpose of this tutorial. At the end there is an appendix to demonstrate how to use data acquired via the AppEEARs web service.
The first step is to define the geographical domain of interest. A convenient way to do this is to use the specialized
UtmDomain.from_spherical_chunk constructor that takes WGS84 coordinates and converts them to an appropriate UTM domain. The UTM zone and coordinates could of course also be specified directly.d = sn.domain.dim3.UtmDomain.from_spherical_chunk(
min_latitude=46.15,
max_latitude=46.30,
min_longitude=-122.28,
max_longitude=-122.12,
)
# Have a look at the domain to make sure it is correct.
d.plot()