Geography Reference
In-Depth Information
Earth's Natural Disasters DataBase), a new version of a geoinformation
system (GIS). The algorithms implemented in ENDDB allow visualizing
a selected part of a current catalog in a pseudo-3D background map. With
its mathematical support, the ENDDB system can plot frequency
dependences of magnitudes or sizes (crater diameters) of events from
various samples, as well as other distributions of integrated parameters in
time and space, or their relationships with one another.
The expert earthquake database (EEDB).
There existed an earlier
GIS version, an EEDB system [3], which had a wide range of
seismological applications. It was gradual transition from a conventional
GIS (originally created by the authors) to a high-tech expert system
updated by including successively various mathematical methods for
earthquake data processing, new parameters of seismic regime, and
advanced representation tools. The realized algorithms [4] allow the user
to compute and visualize maps and diagrams of seismicity parameters
(slope of magnitude-recurrence curves, seismic quiescence, earthquake
density, etc.), to reveal clustering of events, and remove aftershocks.
Modifications and versions of GIS-EEDB for different geodynamic
regions [5] are illustrated in the chapter with case studies of seismic
anomalies.
Visualization and analysis of EISC data.
Applying the EEDB
system software to EISC data [1] (in the new GIS system, called Earth's
Impact Structures Catalog (EISC) [6]) allows gaining insights into spatial
patterns of impact structures. In addition, the shapes of craters are
constrained using a shaded relief model based on NASA data arrays of
SRTM (Shuttle Radar Topography Mission) and ASTER GDEM (Global
Digital Elevation Model), and the technology of digital mapping. Thus
typical elements of impact craters morphology have been systematized
and can be used as indicators of the crater origin [7].
Gravity data and new applications of GIS ENDDB
. The reliability
of geomorphically expressed diagnostic indicators of crater shapes was
checked against geophysical features revealed by gravity data, namely,
the presence of tail-shaped negative gravity anomalies produced by large
impact craters.
By mapping gravity anomalies, using our shaded relief
model and ―Global marine gravity‖ data (V18.1), we can verify the
gravity patterns associated with impact cratering and check their validity
as tracers of bolid trajectories. Gravity data also have seismological
implications and can be used to identify seismic blocks, lineaments, and
other structures detectable with GIS ENDDB mathematical tools and thus
to analyze the spatial patterns of seismicity.
