Tsunami Detection System
According to an easily understood, early warning system is a system that informs the possibility of danger before the danger occurs. Including biological systems possessed by living things and man-made system results. Which includes biological systems is a pain and fear (which is generally a part of the instinct) owned natural living things. While that includes artificial system is a system designed to gather the data human-related data and process into the possibility of danger parameters. Man-made system is made for civilian purposes and there is also special for military purposes. In this early warning system for tsunamis, including for civilian purposes. Similarly, smoke detector, earthquake detectors, and so forth. While early warning tool for the military include detector of ballistic missiles, nuclear attack detection, warning devices antirudal fighter, and so forth.
Technology is always dedicated in everything. Social field, for example, technology can help to suppress the number of deaths due to natural disasters that occur.
Recent years the Indonesian nation is often hit by natural disasters in the form of floods, landslides, earthquakes, tsunamis, and the mountain brush which recently discussed because of rampant menghawatirkan condition. These natural disasters are unavoidable, but as long as can be handled and handled well it will reduce the number of casualties and losses incurred.
One way to overcome that is by designing an early detection system modeling the arrival of the tsunami. Detection system may be the sensors that can see changes in circumstances surrounding the event of a tsunami phenomena which are usually marked with changing sea levels or the density of water known as the siltation. Therefore, this detection system can be used as alternatives to sniff out the natural disaster. This sensor can send a sinusoidal signal which will be accepted by BMG (Meteorological and Geophysical Agency) through the radio circuit at a frequency of 438 to 470 MHz. This intensity level changes can affect the signal amplituda changes.
In the design and simulation modeling intensity-detection system (siltation), the threshold (threshold) of the conditions that can be identified as the arrival of the tsunami signal changes signal levels between 2mV-70mV. So that residents around the site can be evacuated to safer places. Early warning systems for tsunamis usually abbreviated aka TWS Tsunami Warning System. As the name implies, TWS was built to detect natural phenomena that have the potential to bring about the tsunami disaster as well as find the location of the epicenter that caused the tsunami. The report provided by the TWS can be used to predict the damage will be inflicted and the areas that will be affected by the tsunami. This system is divided into two important components, ie sensors network of tsunami detection and communication infrastructure that is useful for early warning. Tsunami warning and evacuation requires vigilance before the tsunami came. The rate of early warning information is very important considering the time interval between the earthquake until the tsunami reaches land quite brief.
There are two types of tsunami early warning: an international early warning and regional early warning. Both rely on the fact that the tsunami moving at 500 – 1000 km / hour (approximately 0,14-0,28 km / sec) at sea, while earthquakes can be detected quickly by seismic waves moving at an average of 14,400 km / h or about 4 km / sec. By considering the seismic wave that appears, it is possible for the forecast period as well as delivery of a tsunami warning to areas threatened by tsunamis. Only, because there is no clear model that can connect the earthquake and tsunami, the warning by seismic waves become less reliable. A more certain method is to use the tool to the seabed observers see the tsunami waves at sea at a distance as far as possible from the coastline.
Delivery Method Warning:
The process of detection and forecasting of tsunami disaster is only half of the TWS process as a whole. Another thing that is not less important in the TWS is to deliver a warning to residents of the area threatened by the tsunami. This can be done through a variety of telecommunications channels (like e-mail, fax, radio, telex, TV, etc.). Thus, emergency messages can be accepted by society, governments, and agencies disaster relief.
SMS Earthquake BMG:
Magnitude 6.6 SR, 29 Nov 06, 08:32:22 pm, Location 2.42 N, 128.10 BT [347 km northeast Labuha, North Maluku], depth of 13 km. TSUNAMI potential [to be forwarded to the community]
Weaknesses:
There was no system that can protect humans from the tsunami disaster that occurred suddenly. Therefore, until now a tsunami early warning has never saved anyone from a sudden tsunami. Nevertheless, the tsunami early warning system can still work effectively if the distance is very much the epicenter. This can provide opportunities for the residents to evacuate. Early Warning System is a specific chain (the critical relationship) between the actions in preparedness with emergency response activities.
Tsunami sniff with Laser Sensor
Tsunami detection technology not to be too sophisticated. Sederhanapun laser technology can be used to sniff. Accompanied by massive earthquake tsunami that occurred in North Sumatra and Aceh some time ago gave a very valuable lesson for the Indonesian people how great the power of tsunami waves pulverized. However, we are surprised when semuapun know that a tsunami actually take a few minutes to several tens of minutes to reach the mainland. Among the time, it is possible actually used to warn coastal residents of danger, so they can move away as soon as possible. Unfortunately this is not happening.
Bitter experience that requires us to find ways to avoid the same experience. One of them, perhaps we can look at Japan, a country prone to both experienced in handling the earthquake and tsunami.
Japan is also an earthquake-prone country has installed an earthquake-detection equipment, both on land and at sea. Equipment installed in the sea is also equipped with a tsunami detection. Tools the program is equipped with super-fast computers and communication facilities. Thus, when the tsunami happened, only in a matter of 2-5 minutes, the complete data about the tsunami threat to the public via broadcast television network. This early warning mechanism, developed in Japan now.
Actually there are several methods that can be used to detect tsunamis developed. One of them is as developed Dr. Sakata, a tsunami expert researchers from the National Research Institute for Earth Science and Disaster Prevention (NIED). Japan, has created a new method using a laser. This method is very simple and very sensitive as the tsunami sensors or sensor shift / pressure. Besides that, tool free of noise because the sensor is sent to far away from the beach is a laser light through optical fiber are all electronic devices placed on the ground.
Figure shows the tsunami-detection system with a laser. There are two separate parts, namely the main sensor is placed on the seabed a few miles from the coast and the monitoring or control on the ground (control room / monitor). Two laser diodes used as light sources as well as a slave oscillator. Of each laser is divided into two parts with a ratio of 9:1. Part of 90 percent is sent to the sensor via fiber optics, as well as back light transmitted through fiber optics to the recipient (control room). The light returned by the sensors will be detected by a photo detector, and then the signal used to lock the laser frequency to the transmission peak of the resonator.Other parts together using fiber coupler to generate a signal and the measured beat frequency.
The main sensor is placed on the seabed in the form of two Fabry-Perot resonator with a free spectral range (FSR) of the same. Each cavity is formed from two mirrors separated by distance and fitted cross Lc (x and y axis). FSR is defined as FSR = C / (2 n Lc), with C is the speed of light (m / sec), n is the refractive index of the medium (= 1) and Lc is the distance between two mirrors. This cavity will only provide the transmission peak when the laser frequency corresponding to (resonate) with FSR of the cavity. Cavity and then inserted into a cylindrical tube made of stainless material, each of which is locked with a wall mirror tube. Form part in such a way that made no difference thicker than the cylinder wall at the x and y (see picture).
If the tube wall exposed to the stresses of tsunami waves, Lc will change that resulted from the cavity FSR changes. Wall thickness differences also resulted from the difference cavity length change of 1 and cavity 2. Figure A shows a graph of the resonator transmission peaks as a function of laser frequency sweep. As illustrated in the graph that with the same pressure difference from the resonator FSR changes 1 and 2. These changes are detected further by beat frequency of two lasers, each locked frequency of the two-cavity. Locking the laser to the peak transmission of the sensor is done by a simple circuit of auto-lock circuit. Figure B illustrates the transmission peak of the sensor viewed using the oscilloscope, while the image C shows the signal after the laser is locked. Seen that the transmission power equal to the peak of the sensor, which means the laser is locked to the well of the sensor. Speed control system is 10 KHz, this speed is enough to anticipate changes in the speed sensor.
Sensor works when both lasers locked properly into each pair of resonator. Then from some of the combined laser light detected beat signal using photo detector.
Light source placed along with the trimmings on the ground. From this tool can monitor changes in the laser frequency corresponding to the height of the tsunami and so on were distributed to the earthquake observation center using phone lines. Change 12 MHz frequency difference is detected for each 1 cm change in the tsunami. For the distance between two mirrors of 10 cm, resonator FSR of approximately 6 GHz, so it will be able to detect a tsunami which reached 5 meters high. The amount of the tsunami that can be detected can be enlarged by enlarging the distance of two mirrors or thicken the tube wall. Sensor-to-surface distance can reach 50-100 km depending on the laser power is used. With the distance sensor 100 km from the coast is also possible to provide early warning for more than tens of minutes to land on the sensor when the tsunami occurred.
So far the tsunami sensor is not a lot of products sold in the market because users are usually government (research institutions), so the price is quite expensive. However, in terms of this sensor technology is not so hard to get 100 percent can be made (assembled) in Indonesia. Of course this requires support from the government to take advantage of the maximum potential of the domestic human resources and work together with experts in Japanese inventor. The problem now, would we do it?
