Geoscience Reference
In-Depth Information
Figure 5d.
Disturbances in
Ez
component of the quasi-static field, orbit 602.
Any disturbances (orbits 482, 546, and 602) from EQ
66
to EQ
69
(see Table 1) are
not observed. Data from orbits 196 and 244 for observations about EQ
16
and EQ
17
is
used as well. The satellite passes (orbit 196) about 13-14 hr before EQ
16
and EQ
17
in
the region of South-West Pacifi c Ocean (Figure 5a). Figure 5e shows two disturbances
in
E
z
component of the quasi-static electric fi eld in relation with seismic activity. The
fi rst change is an increase in
E
z
component of about 8 mV/m, 13 hr before EQ
16
. The
second change represents another increase in
Ez
component of about 10 mV/m, 14 hr
before EQ
17
. These data is taken in a medium quiet day K
p
= 4. We can also observe an
increase in the
E
z
component of about 8 mV/m, 55 hr after EQ
17
.
Figure 5e.
Disturbances in
E
z
components of the quasi-static field, orbit 196.
Any disturbances (orbit 244) from EQ
16
, EQ
17
(see Table 1) are not noted. Similar
anomalies in the quasi-static electric fi eld are summarized as an increase in the vertical
component of the quasi-static electric fi eld of about 2-10 mV/m, around 20 hr before
to and 96 hr after earthquakes EQ
61
(orbits 482 and 483), EQ
66
(orbits 482 and 546) and
EQ
67
(orbits 505, 547, and 581). All of them are listed in Table 1.
Kuril Island and Aleutian Islands
We take observations over seismic events in the region with the help of two satellite
orbits (240 and 283) in the time period August 16-September 9, 1981 (Figure 6a). Two
