Geography Reference
In-Depth Information
3)
Inspection of the JMA catalog has shown that its completeness is the
best within the interval of 2002-2013 and the earthquake magnitudes
from 3.5 to 6.5 are the best representative;
4)
The map of long-term seismic activity normalized to K = 15 (energy
scale) shows the greatest activity in the the Japan offshore area for the
past 20 years. It is next to the Fukushima Prefecture coast, with the
maximum near Hitachi city.
5)
The medium-term and long-term anomalies appeared before the
Tohoku event in several seismicity parameters, including 1) weakly
pronounced decrease in
b
for the past decade prior to the event; 2)
flattening of the
K
avr
(fracture density) curve for the past 6 years; 3)
formation of quiescence zones for the past 2 years; 4) prominent
positive anomalies of relative energy gradient formed a year before
the shock.
All these features may indicate seismic stabilization in the nucleation area
preceding the Tohoku great earthquake.
P
ART
3.
V
ISUALIZATION AND
A
NALYSIS OF
EISC-D
ATA
A. V. Mikheeva
The catalog of the Earth's Impact structures, available at the website of
ICM&MG [1, 6, 58] was created by Anna Mikheeva in 2005 based on
different reference data: published evidence (papers, books), Abstract
Journals, data deposited in VINITI (section ―Geology and Geophysics"), as
well as personal communications. As a result, the first Russian Internet catalog
and a Complete Database of all observed, probable, potential, and even
erroneously inferred structures of extraterrestrial origin have been compiled.
There are fields with key parameters indicating the location of footprints left
by an impact or an explosion of a cosmic body (CB) on the Earth's surface:
event name (and/or geographical location, territory), continent or ocean code,
underwater (*) and comet (‗) marks, the validity index according to 5-grade
probability scale (from 0 to 4, Figure 23a), coordinates and geometrical size of
the structures (latitude, longitude, diameter), age (or date) (Figure 23a), the
relevant text and graphical information (as hyperlinks), and many other fields
in the extended version (depth, number of objects, erosion rate, gravity and
