3-D P wave velocity model for the Puget Basin
region
Interactive West-to-East Cross
Section View:
This page is an interactive cross-section view through a 3-D
high resolution P
velocity model of the greater Puget basin region of western
Washington. The model is derived from inversion of active source
and earthquake
arrival times. Abbreviated information relevant to the velocity model
and its
construction is given below. The display requires Javascript browser
support (Javascript must be enabled in the users browser). A large
amount of data (> 20 Mb) must be loaded for the interactive display
to work, so please allow time for the loading of the data.
The top display is a map view of the Puget
basin
region, with coastlines and other geographic features, lat/lon grid at
1/2 degree
intervals and seismograph stations (triangles). The geographic origin
of the
x-y coordinates is -124.5 W and 46.25 N (typically off of the plot
area). The
bottom cross-section
display is a vertical (slice) through the velocity model
taken along the heavy red line in the map display. The dashed red lines
define the corridor within which earthquake hypocenters (black dots)
are
projected
laterally onto the cross-section plots. Only earthquakes used in
the inversion computations are shown, so this is a highly selected view
of the regional seismicity. The distance from the origin (eastward) is
shown by the white number at the lower
right of
each cross section.
The color scaling for wave speed is identical for all plots, and is
shown by the color scale to the right. Hashered regions on the
cross-section indicate cells in the model that are not directly
constrained by rays used in the inversion. The vertical-to-horizontal
scale is approximately 1:1.