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EARTHQUAKE DETECTION USING FM
PRESENTATION BYMR. VISHAL KUMAR
RADIO
MR. ARIJIT NAG
3rd YEAR ,ELECTRONICS AND COMMUNICATION.MALLABHUM INSTITUTE
OF TECHNOLOGYBISHNUPUR, BANKURA
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CONTENTS
• what is an Earthquake?
• Causes and Effects of an Earthquake.
• Damages by Earth quake.
• FM and its position in Electromagnetic Spectrum.
• Propagation of Very High Frequency Wave.
• Anomalies Observed in the Reception of FM Radio Waves.
• Equipments Used For the Detection of Anomaly in FM.
• Possibility of Earthquake Detection by observing the Anomaly
•
in FM.
Relation between Earthquake and Ionospheric Plasma Density
Variation.
Classification of Anomalies.
•
• Earthquake Prediction using Kushida’s Methodology.
•CONCLUSION
WHAT IS AN EARTHQUAKE ?
• An earthquake (also known as a
quake, tremor or temblor) is
the result of a sudden release of
energy in the Earth's crust that
creates seismic waves.
• These seismic waves travels
through earth’s interior.
• An earthquake's point of initial
rupture is called its focus or
hypocenter. The epicenter is the
point at ground level directly
above the hypocenter.
• Absolute magnitude is measured
in RICHTER or MOMENT
MAGNITUDE SCALE and felt
CAUSES AND EFFECTS OF AN
EARTHQAUKE
• May be natural or
man-made.
EFFECTS
•Shaking and
•
•
•
•
ground rupture
Landslides and
avalanches
Fires
Soil liquefaction
Tsunami
DAMAGES BY EARTHQUAKE
FM AND ITS POSITION IN
ELECTROMAGETIC
SPECTRUM
• Electromagnetic Waves
• FM stands for
frequency modulation.
• Usually the bandwidth
of FM lies within
88MHz -- 108MHz.
• VHF (Very High
frequency) range is
from 30MHz to
300MHz and FM uses
this range.
PROPAGATION OF VERY HIGH
FREQUENCY WAVES
• VHF propagation is called Space wave
propagation.
• Space wave propagation has two
components-(a)Direct component,
(b)Indirect or ground reflected component.
• Direct component is propagated by two
methods
• (a)Line of sight propagation:-Limited by
Curvature of Earth and Height of transmitting
and receiving antennas.
• (b)Scatter propagation:-occurs in ionospheric
E-layer due to blobes of air mass and from
the ionized trials of meteors ,geomagnetic
field variation etc.
• Usually the VHF wave penetrates the
ionosphere and are lost , but due to the high
ANOMALIES OBSERVED IN THE
RECEPTION
OF
FM
RADIO
• Anomalous or strange unwanted
reception of radio waves occur beyond
the line of sight receiver set. WAVE
• Short pulses or echoes(duration
100ms) are observed in radio reception
due to entry of meteors into the earth’s
atmosphere or passage of aircrafts.
• Thunderstorms and other weather
activities, Geomagnetic disturbances
are also responsible for anomalous
reception.
• Sporadic E layer causes baseline
fluctuation.
Base line fluctuation due to sporadic E
EQUIPMENTS USED FOR THE
DETECTION OF ANOMALY IN FM
• FM receiver /VHF digital
•
•
•
tunning receiver tuned
slightly offset to the
frequency of the fm radio
station.
Yagi-Uda antenna(5
element)-is directed
vertically and normal vector
of antenna plane is directed
with an offset angle towards
a fm station located beyond
line of sight.
Center tunning meter-output
voltage proportional to
difference between tuned
frequency and input
frequency
Chart recorder-records
POSSIBILITY OF EARTHQUAKE
DETECTION
BY OBSERVING
• Radio
echo used to appear one to
several times in a day and before
two to threeTHE
weeks of earthquake
ANOMALY
IN
FM
occurrence. After two to nine days
•
•
•
from the last appearance of echo
earthquake have occurred.
High density plasma in ionosphere
E layer over the epicenter before
and after earthquake.
A co-seismic EM phenomenon has
been detected in VHF band.
The VHF emissions have been
continued for about three hours,
after the seismic wave.
• The starting times of VHF
emissions corresponded to arrival
Detected co-seismic EM
waves in VHF band at
RELATION BETWEEN
EARTHQUAKE AND
• possible mechanism for the generation of electromagnetic
PLASMA
wavesIONOSPHERIC
in the lithosphere is to be identified
with the microfracturing process of rocks. These micro-fractures, in turn,
involve the
breaking of a large
number of atomic bonds, i.e.
DENSITY
VARIATION
•
the covalent or ionic bonds giving rise to the crystalline
structure of the rocks. The formation of unbalanced charge
distributions, of opposite sign, on the opposite sides of the
micro-fractures is to be expected and, consequently, the
onset of strong local electric fields which is explaining geoelectric and geomagnetic fields anomalies as well as
development of strong ionospheric perturbations preceding
strong earthquakes.
Ionospheric perturbations by acoustic gravity waves
generated by intensive gas discharges from the crust (mainly
CLASSIFICATION OF
ANOMALIES
•CD:-charge-discharge
•
•
•
anomalies
BT:-base-line thickness
anomalies
CDS:-charge-discharge
dominant with
superposed BT
BTS:-base line thickness
dominant with
superposed CD
EARTHQUAKE PREDICTION
USING KUSHIDA’S
• Yoshio Kushida and Reiki Kushida
first discovered
and implemented VHF
METHODOLOGY
band in EQ detection.
Forcast of date
• In most cases the first appearance
precedence is in the range of 4-8
days.The maximal anomaly
precedence is in the range of 2-3 days
and preseismic pause in about 1
day.An early warning can be made
after the first appearance of the
anomaly.the date of future earthquakes
can be forecasted by observing the
preseismic maximal of the anomaly
FORECAST OF FOCUS
• Each receiver is assumed
to have a
LOCATION
sensitivity region.
• Mainly depends on CD component.
• When CD anomalies or CDS
•
•
•
anomalies are observed by receiver,
sensitive region contain the foci of
future earthquake .
BT anomalies are observed if the foci
of the future earthquake is out of the
sensitive regions.
BTS anomalies are observed by vicinal
receiver in the case the foci of the
future earthquake is located close to
the border of the sensitive region.
The time constant of CD component is
about 5-10 min for underground
earthquake. Time constant is about 1-2
min when foci of future earthquake is
located closer to the sea-shore
FORECAST OF MAGNITUDE
• Depends on the BT
component.
Depends on significance of
CD anomaly
where v0 is the usual baseline
thickness
the strength of BT and
BTS anomaly is measured
by
•
•
CONCLUSION
•92 Kushida predictions mentioning the
possibility of M ≥ 5.5 event, whereas there
were 49 M ≥ 5.5 earthquakes in the
Japanese region.
REFERENCES
•Y.Kushida and
•
R.Kushida,”On the
possibility of
Earthquake Forecast
by Radio observation
in the VHF band”
T.Yoshida and
M.Nishi,”Co-seismic
VHF Emission
Associated with
Earthquakes”