Geoscience Reference
In-Depth Information
Figure 3b.
Disturbances in
Ez
components of the quasi-static field, orbit 215.
Figure 3c.
Disturbances in
Ez
components of the quasi-static field, orbit 258.
The pass of INTERCOSMOS-BULGARIA-1300 (orbit 258) 84-85 hr before the
seismic manifestations is shown in Figure 3c. The disturbances in the
E
z
component
of the quasi-static electric fi eld are the following ones: The fi rst one to the north of
the earthquake epicenters (projection over the equipotent magnetic fi eld lines in
the near-equatorial ionosphere at satellite altitude) and second one in the magnetic
conjugate region of about 2-3 mV/m for EQ
37
. The both of them are shown in Fig-
ure 3c. It should be noted that these measurements of orbits (215 and 258) are made
in a quiet day (K
p
= 3), so the observed anomalies could not be caused by a solar-
terrestrial disturbance.
Eastern Canada and Labrador Sea
Two events (EQ
6
, EQ
23
) are recorded on August 18 and August 24, 1981 with magni-
tudes M 5.1 and 4.8 in the time period August 18-24, 1981, respectively (see Table 1).
The EQ
6
occurred in the region of Eastern Canada. The causes of earthquakes in the
Eastern Canada are not well understood.
