Geoscience Reference
In-Depth Information
• We focus our attention on the considerable rising of data only of nighttime ob-
servations for the ionospheric anomalies that are in possible associations with
earthquakes.
Table 2.
General results from observations.
Total number of earthquakes from USGS website
73
Total number of positive, uncertain and negative effects
from main shocks for twenty six orbits
92
Total number of positive and negative effects
87
Number of possible positive effects
52
Number of pre effects
27
Number of nighttime pre effects for different latitudes
25
Near-equatorial latitudes
Low latitudes
Middle and hight latitudes
2
2
2
6
1
2+1
7+1
1+0
-∆t,h
-∆t,h
-∆t,h
-∆t,h
-∆t,h
-∆t,h
-∆t,h
-∆t,h
≤12
≤11-20
≤12
≤13- 25
≤306
≤12
≤80
≤80
M
Δ
λ, deg
M
Δ
λ, deg
M
Δ
λ, deg
M
Δ
λ, deg
M
Δ
λ, deg
M
Δ
λ, deg
M
Δ
λ, deg
M
Δ
λ, deg
4.8-4.9≤1-9
5-6≤13
4.8-4.9≤1-9
5-6≤1-14
7-8≤1
4.8-4.9≤1-9
5-6≤1-18
6-7≤18
Number of nighttimepost effects for different latitudes
Low latitudes
Middle latitudes
Hight latitudes
1
5
1
7
3
1
3
-∆t,h
-∆t,h
-∆t,h
-∆t,h
-∆t,h
-∆t,h
-∆t,h
≤80
≤7-19
≤300
≤80
≤96
≤91
≤96
M
Δ
λ, deg
M
Δ
λ, deg
M
Δ
λ, deg
M
Δ
λ, deg
M
Δ
λ, deg
M
Δ
λ, deg
M
Δ
λ, deg
4-8-4.9 ≤ 1-14
5-6 ≤ 6-16
7-8≤20
4.8-4.9≤1-14
5-6≤1-14
6-7≤9
5-6≤1-14
Light Earthquakes
Over the earthquake source regions of earthquakes with magnitude M 4.8-4.9 at dif-
ferent latitudes, sometimes, but not always, disturbances (bulges) in the quasi-static
electric field could be observed. Disturbances from light earthquakes with depth >117
km are not established because these seismic manifestations are at a relatively low
energetic level and in a great depth. There are pre-effect disturbances of about 3-10
mV/m 12 hr before for all different latitudes and 80 hr after earthquakes for low and
middle latitudes.
Moderate Earthquakes
Concerning Near Equatorial Latitudes
The anomalies in the quasi-static electric field at near-equatorial latitudes show mainly
an increase in the vertical component
E
z
of about 5 mV/m during a period of 11-20 hr
before moderate earthquakes in Northern and Southern Hemispheres. Similar effects
are also observed in the magnetic conjugate region. Disturbances are observed for
