31-05-2012, 11:10 AM
Seismic Alert Through GSM Network
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INTRODUCTION
Earthquakes strike without warning. The resulting damage can be minimized and lives can be saved if the people living in the earth-quake prone area are already prepared to survive the strike. This requires a warning before the strong ground motion from the earthquake arrives. Such a warning system is possible because the energy wave released at the epicenter of the earthquake travels slower (at 3.5 to 8 km/s) than light.
The warning signal from the earthquake epicenter can be transmitted to different places using the using the satellite communication network, fibre-optics network, pager service, cell phone service or a combination of these.
In India, for earthquake prone states like Gujarat, a seismic alert system using the global system for mobile communication (GSM) network spread throughout the state is proposed.
This system does not try to find the epicenter or the fault line caused by the earthquake. It simply monitors the earth vibrations and generates alert signal when the level of earth vibrations crosses a threshold.
Time to alert is critical. But in generating the alert quickly, there are possibilities of false alarm. In the system proposed here, an attempt has been made to reduce the possibility of false alarm.
HOW DEADLY ARE THE WAVES GENERATED BY EARTHQUAKE:
When an earthquake occurs, it releases energy in the form of waves that radiate from that earthquake source in all directions. Different types of energy waves shake the ground in different ways and travel through the earth at different velocities. The fastest waves are called primary (P) waves. These are compressional in nature like sound wave, and compress and expand material in their direction of travel. P waves move at a speed of 8 km/sec.
Secondary (S) waves have the characteristics similar to the waves on the surface of water. These move the earth up and down perpendicular to the direction of their motion. S waves are slower than P waves, moving at half the velocity of P waves (4 km/second).Vertical ground motion generated by S waves is highly damaging to the structures.
However, most structural damage is caused by the surface waves that are slower than S waves. Called Love and Rayleigh, these waves shake the ground horizontally.
Destruction also depends on the frequency of ground vibrations. P and S waves have higher frequency of vibration, which shakes the low-rise buildings. The Love and Rayleigh waves have less than 1 Hz vibrations, which cause high rise buildings to vibrate.
Slower waves, which have more damaging characteristics, reach distant places much later.
COMMUNICATION SYSTEM AND THE WAY IT COMMUNICATES WITH DANGER
This GSM based alert system monitors the earth vibration using a strong motion accelerometer at the earthquake prone area and broadcasts an alert message to towns and villages through the cell phone network existing throughout the state. Here mobile phones are used as transmitters and receivers.
[attachment=23632]
INTRODUCTION
Earthquakes strike without warning. The resulting damage can be minimized and lives can be saved if the people living in the earth-quake prone area are already prepared to survive the strike. This requires a warning before the strong ground motion from the earthquake arrives. Such a warning system is possible because the energy wave released at the epicenter of the earthquake travels slower (at 3.5 to 8 km/s) than light.
The warning signal from the earthquake epicenter can be transmitted to different places using the using the satellite communication network, fibre-optics network, pager service, cell phone service or a combination of these.
In India, for earthquake prone states like Gujarat, a seismic alert system using the global system for mobile communication (GSM) network spread throughout the state is proposed.
This system does not try to find the epicenter or the fault line caused by the earthquake. It simply monitors the earth vibrations and generates alert signal when the level of earth vibrations crosses a threshold.
Time to alert is critical. But in generating the alert quickly, there are possibilities of false alarm. In the system proposed here, an attempt has been made to reduce the possibility of false alarm.
HOW DEADLY ARE THE WAVES GENERATED BY EARTHQUAKE:
When an earthquake occurs, it releases energy in the form of waves that radiate from that earthquake source in all directions. Different types of energy waves shake the ground in different ways and travel through the earth at different velocities. The fastest waves are called primary (P) waves. These are compressional in nature like sound wave, and compress and expand material in their direction of travel. P waves move at a speed of 8 km/sec.
Secondary (S) waves have the characteristics similar to the waves on the surface of water. These move the earth up and down perpendicular to the direction of their motion. S waves are slower than P waves, moving at half the velocity of P waves (4 km/second).Vertical ground motion generated by S waves is highly damaging to the structures.
However, most structural damage is caused by the surface waves that are slower than S waves. Called Love and Rayleigh, these waves shake the ground horizontally.
Destruction also depends on the frequency of ground vibrations. P and S waves have higher frequency of vibration, which shakes the low-rise buildings. The Love and Rayleigh waves have less than 1 Hz vibrations, which cause high rise buildings to vibrate.
Slower waves, which have more damaging characteristics, reach distant places much later.
COMMUNICATION SYSTEM AND THE WAY IT COMMUNICATES WITH DANGER
This GSM based alert system monitors the earth vibration using a strong motion accelerometer at the earthquake prone area and broadcasts an alert message to towns and villages through the cell phone network existing throughout the state. Here mobile phones are used as transmitters and receivers.