23-01-2013, 02:38 PM
A TECHNICAL PAPER ON Seismic Alert Through Gsm Network
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ABSTRACT:-
When an Earthquake strikes, thousands are left dead, lakhs are left homeless because they strike without any warning. This is evident from the two most devastating earthquakes of recent times.One in Gujarat in 2001, and the other one not only caused a destruction by itself but also led to a TSUNAMI. So,there must be some way to detect the occurence of these killer-quakes beforehand. This is where the GSM comes into prominence. GSM stands for "Global System for Mobile Communication".
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.
Since earthquakes release tremendous amount of energy, this energy may be converted into a signal by the accelerometer. The signal is then transferred to the mobile receiver handset via short message service (SMS). The handset, in turn, will transfer it to the base transceiver stations (BTS) if it is within 10 to 17 kms. of the BTS. Otherwise, it may require a repeater for transferring data to the cell phone network.
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.
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/speed.
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.
EARTHQUAKE- SENSOR NETWORK:
Earthquake sensor (strong motion accelerometers) are deployed at known epicenters, fault line zones and earthquake-prone areas.
Each sensing location should have two accelerometers placed two to three meters away from each other. The purpose of installing two accelerometers at each place is to detect and eliminate the local vibration noise, which can give false signals (vibration) to the accelerometer. An interface unit, which has to be developed, will monitor both the accelerometers. It will act only when both the accelerometers give the same signals.
Since this is only an alert network and does not find out the location of the epicenter, only the discrete magnitude levels will be detected and any magnitude above the preset threshold level will be transferred to the mobile receiver handset via short message service (SMS). The handset, in turn, will transfer it to the base transceiver stations (BTS) if it is within 10 to 17 kms. of the BTS. Otherwise, it may require a repeater for transferring data to the cell phone network.
The handset should have auto dialing facility and be pre-loaded with a fixed dialing number and fixed message. Whenever the handset gets a signal (pulse) from the interface unit, it goes into the auto-dialing mode and transfers data to the network and waits for the next pulse with the same number and message.
DECISION SYSTEM:
When an SMS is sent from the mobile handset, it first goes to the SMS server of the mobile network, then to the destination receiver handset. If the same message has to be sent to different locations (receivers), the transmitter handset has to dial different numbers for different destinations.
But in this proposed system, on a single transmission, the message should go to different predefined locations. This is possible if the SMS server of the mobile network is programmed for such a facility. In fact, this type of facility already exists in the GSM network in the form of `cell broadcast’. But it is not advisable to disturb the main server specially for this system. Another application server may be included in the network for the alert system, which will work as the interface between the network (SMS) server and the transmitter located at different earthquake-prone areas of epicenters.
At the epicenter, the interface unit triggers the handset as soon as it receives P and S waves of the predefined magnitude. The handset is always ready with the fixed message and destination number. Here the destination is the application server, which has been included for the proposed system and should be connected to the SMS server of the mobile telephone (GSM) network. It also acts as an interface between the single source transmitter (epicenter) and multiple receivers installed at different towns and villages.
All the source handsets (placed at different locations) for sending the alert messages) should be registered at the application server. As soon as the application server receives an alert message (through the SMS server) from a particular registered source handset or transmitter, it first checks whether it is for P wave or S wave.
ALERT-DISSEMINATION NETWORK
The alert-dissemination network is a simple cell phone network (GSM) in SMS mode, which already exists in most of the states in India. Alert messages are transferred to the destination handset through the mobile network system in SMS mode. The receivers are installed at different places as individual units or in groups. These should have an interface unit to read the message and take action to disseminate the alert message to the public. The alert receivers could be attached to the civil defence sirens and broadcast systems, and also installed at Government Offices that are responsible for disaster management.
TIME-TO-ALERT:
In this system, time-to-alert is the time between the actual occurrence of the earthquake at the sensing point and the audio or text message output at the public or the Government Offices. End-to-end communication delay will be very less, provided all the transmitters (handsets) placed at different epicenters are given the top priority for communication in SMS mode. For this, a permanent instruction (through the application server) has to be given to the SMS server of the communication network so that whenever an alert message comes from the identified locations (registered to the application server), the server gives it the top priority and transmits it to the destination immediately.
Time to transfer the alert signal from the epicenter to the application server will be a maximum of three seconds because the SMS server will give priority to this message.
CONCLUSION:
List of Places where danger can be averted and property saved :
Once an alert message is received,
Nuclear Power Plants, Airport Operations, oil pipe-lines, refineries,
Gas distributions can be shut down. Trains can be stopped. Fire stations, Hospital operation rooms can be alerted. Emergency generators can be started.