Note
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Focal mechanisms
The pygmt.Figure.meca
method can plot focal mechanisms or beachballs.
We can specify the focal mechanism nodal planes or moment tensor components
as a dictionary using the spec
parameter (or they can be specified as a
1-D or 2-D array, or within a file). The size of the beachballs can be set
using the scale
parameter. The compressive and extensive quadrants can
be filled either with a color or a pattern via the compressionfill
and
extensionfill
parameters, respectively. Use the pen
parameter to
adjust the outline of the beachballs.
import pygmt
fig = pygmt.Figure()
# Generate a map near Washington State showing land, water, and shorelines
fig.coast(
region=[-125, -122, 47, 49],
projection="M6c",
land="grey",
water="lightblue",
shorelines=True,
frame="a",
)
# Store focal mechanism parameters in a dictionary based on the Aki & Richards
# convention
focal_mechanism = {"strike": 330, "dip": 30, "rake": 90, "magnitude": 3}
# Pass the focal mechanism data through the spec parameter. In addition provide
# scale, event location, and event depth
fig.meca(
spec=focal_mechanism,
scale="1c", # in centimeters
longitude=-124.3,
latitude=48.1,
depth=12.0,
# Fill compressive quadrants with color "red"
# [Default is "black"]
compressionfill="red",
# Fill extensive quadrants with color "cornsilk"
# [Default is "white"]
extensionfill="cornsilk",
# Draw a 0.5 points thick dark gray ("gray30") solid outline via
# the pen parameter [Default is "0.25p,black,solid"]
pen="0.5p,gray30,solid",
)
fig.show()
Total running time of the script: (0 minutes 0.156 seconds)