-for saving innocent lives Tsunami and Earthquake early warning system -for saving innocent lives

Overview 1. Introduction 2. Tsunami 3. Seismic waves 4. Bottom pressure recorder 5. Buoy 6. Epicenter (originating point) 7. Tsunami reporting system-Working 8. Earthquake alarm system-Working 9. Conclusion

INTRODUCTION A satellite-based communication system is introduced to give early warning of tsunamis and earthquake through alert signals. The pacific Marine Environmental Laboratory (PMEL) has developed this technology. This single alert system for both tsunami and earthquake senses the changes of the water-level pressure on the sea floor and wave magnitude due to an earthquake on the earth surface. The earthquake alarm system consists of reporting terminal(seismic stations) which is very similar to the tsunami reporting terminal, except that an accelerometer is used in place of the Bottom pressure recorder

Tsunami Tsunami is a Japanese word made of ‘tsu’ and ‘nami’ characters where ‘tsu’ means ‘harbour’ and ‘nami’ means ‘wave’ It is a series of ocean waves generated by a rapid disturbance of the sea water due to earthquakes occurring below the ocean floor. Commonly caused by land slides, infrequently by volcanic eruptions and very rarely by a large meteorite impact in the ocean. Caused by Seismic waves(energy waves). Travel around 890 kmph i.e., the speed of jet airplane when the ocean is 6100 meters deep. They can move from one side of the Pacific Ocean to the other side in less than one day.

As the depth of water decreases, the speed of the tsunami diminishes, but the change in total energy remains constant. As tsunami enters the waters of coastlines, the velocity of its waves diminishes and wave height increases.

Seismic waves Seismic waves are the energy waves that generally travel through the Earth. They results from an earthquake, explosion, or a volcanic eruption. When an earthquake occurs, it releases energy in the form of waves(seismic 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.

Types Types of waves Body waves Surface waves Primary waves Secondary waves Rayleigh waves Love waves

Primary waves Also called pressure waves that travel faster than other waves through the earth. As they are the first waves that reaches the seismograph stations, so they are called as “Primary waves”. These waves can travel through any type of material, including fluids. They travel at the speed of sound. Typical speeds are 330 m/s in air, 1450 m/s in water and about 5000 m/s in granite. P-waves move at the rate of 8 km per sec i.e., twice the speed of S waves.

Secondary waves S-waves are slower than p-waves and move at half the speed of p-waves. These waves arrive at seismograph stations after the faster moving P waves during an earthquake. Vertical ground motion generated by s-waves is highly damaging to the structures. They displace the ground perpendicular to the direction of propagation.

Love waves and Rayleigh waves These are slower surface waves that causes most structural damage. Love waves shake the ground horizontally perpendicular to the direction of motion Love waves usually travel slightly faster than Rayleigh waves, about 90% of the S wave velocity, and have the largest amplitude. Rayleigh waves, also called ground roll, that travel as ripples with motions that are similar to those of waves on the surface of water .

BPR BPR stands for Bottom Pressure Recorder. It is a Special type of equipment to record the waves deployed at the bottom of the ocean. Bottom pressure recorders are placed at different places at the grounds of ocean. As if any BPR senses the waves beyond the threshold value ,they send the signals to Tsunami Buoy.

BUOY

Epicenter It is the point where an earthquake or underground explosion originates. It is the area of greatest damage. Generally 3 seismic stations are needed to find the epicentre of an earthquake because all three radial circles made by the stations will only meet at one point. (example: if you only had to circles they would meet at two different points)

How to measure the Epicenter ?

How are Earthquake Magnitudes Measured? Measured on the Richter scale. The Richter magnitude is calculated from the amplitude of the largest seismic wave recorded for the earthquake. Measure the distance between the first p wave and the first s wave. Find the point on the left side of the chart and the mark that point. Measure the amplitude(height) of the strongest wave. Find the right side of the chart and mark that point.

Distance between first P and S wave Richter scale reading Height of strongest wave

Real-time tsunami reporting system Main function -- is to record seismic waves followed by tsunami waves and transfer this data to the warning dissemination center through satellite communication media. Brief look(parts)

s waves will hit the nearest seismic stations to the epicenter. Earthquake alarm system In the event of an earthquake of r-scale magnitude greater than 6, s waves will hit the nearest seismic stations to the epicenter. These stations, in turn, will transmit this data to the network manager through the satellite channel. The network manager automatically selects from the computer the places where warning is to be disseminated, within 40 to 400 km away from the reporting terminal. It transmits the prerecorded siren or audio to selected warning receivers stationed 40 to 400 km away from the reporting terminal.

Brief look:

Conclusion :

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