how is piezo sensor applicable for earth quake monitoring?
94775
A Piezo sensor is basically a quartz crystal.  When the crystal is subjected to stress or shock, it generates an electric voltage.  This is called the Piezoelectric effect. \nThe sensors are then connected to measuring and recording equipment that monitors the sensor for the output of any voltages from the crystal.\n\n\nPiezo sensors are placed in specialized mechanical strain gauges that can detect very minute movements...and thus can detect movement within the surface of the Earth.
658052
It's an amplifier used to drive piezo electric devices that usually require large voltages (50-200V). e.g. a servo amplifier will be needed if you want to control a piezo device using a computer with a +/-5V card.
592564
Piezoelectric crystals will deform when a voltage is applied to them. If the voltage is an alternating one, they will deform one way, then the other way,. If the voltage is alternating rapidly, the crystal will flex rapidly. If the alternating signal is in the audio range, the crystal will emit sound. (Some very small, lightweight headphones work this way.)\n\nThe opposite is true also. When the crystal is mechanically deformed (vibrated), it will generate a tiny voltage. So they can also be used as microphones. Some piezoelectric crystals are actually ceramic materials. \n\nThey will respond at ultrasonic frequencies, and so are used as transducers-- sources and sensors.\n\nThe way the crystal is made inside is that there are layer upon layer of the same kind of molecule lined up, all in the same direction. These molecules are usually polarized, with a free electron on one end and none at the other end.\n\nSo if a thin film of metal is electroplated on both sides of the crystal (and you have to cut the crystal carefully, to make sure you have the molecules lined up right) you can solder wires to those metal platis and use them as electrodes. When a voltage is applied to one side, the molecules want to rotate in place (without stepping out of formation) as far as they can. The electrons repel one another, and this is what causes the deformation.\n\nWhen the polarity of the voltage reverses, the molecules want to rotate the opposite direction (again, without steping out of formation.) The electrons are repelling on the opposite side.\n\nIf too high a voltage is applied, the molecules break formation, and the crystal cracks. The voltage causes a little spark like an electric arc, that ruins the device.\n\nIn addition to the man-made ceramic materials, quartz, tourmaline and Rochelle Salts have these properties. Radio hams use quartz crystals to keep their transmitters on the right frequencies.\n\nIf you are intersted in things of this type, I suggest taking electronics courses. It will be a challenge, but you seem to have an interest, and I know you will enjoy someday being able to build your own ultrasonic devices, like rangefinders and echo-locators. Good luck!
376357
there are many earthquake observatories in japan.\n we can get almost correct information within 10minutes\n but sometimes we cannot count on the machines.earthquakes\n occur everyday.
948942
Go to http://en.wikipedia.org/wiki/Earthquake#Size_and_frequency_of_occurrence for your answer.\n\nGood Luck!!!
88180
Yes, to a degree. Earthquakes can be predicted using past locations, active faults, geological recurrence times, and fault slip data rates from plate tectonic and satellite data. This level of prediction is time-independent, so it will only give a likelihood of an earthquake's magnitude with path and locational effects. This is useful for building design, land use planning, and estimating earthquake insurance, but it doesn't predict when it will happen. \n\nMore and more data is being collected on past earthquake movement using trenches dug into faults and measuring the traces of paleomovements. Geodetic instruments are now collecting real-time data on the relative movement of various parts of the continent using satellite measurements. As more data is collected it may become easier to add a time-dependent portion to a prediction. The USGS is posting probabilities like this for some faults, but are often leaving the time period open for 50 or more years. \n\nResearch in the US has mostly focused on better understanding earthquakes, especially after an unsuccessful attempt to monitor precursors and predict an earthquake near Parkfield, California. In Japan there has been a growing realization that earthquake prediction may not be realistic in the aftermath of Kobe. In China approximately 30 false alarms have caused major problems and the government is discouraging predictions. \n\nThere are a number of creative methods that have been proposed such as tidal forces, animal behavior, and alignment of planets, but none of these has any statistically proven validity. In fact, many of these predictions are made so broadly that the normal occurrence of earthquakes tends to make them look successful. \n\nYou might want to read this article in Nature:\nhttp://www.nature.com/nature/debates/earthquake/index.html\nand here is a description of the Parkfield effort:\nhttp://www.geophys.washington.edu/SEIS/PNSN/INFO_GENERAL/eq_prediction.html
746545
There are earthquakes all the time.  Do you mean a destructive one?  That would be the quake that interrupted a game during the 1989 World Series when the Giants were playing at home.  Do you mean one some people just barely felt or noticed?  Earlier this month.  Do you mean one detected only by seismograph?  Probably within the last fifteen minutes.\nThe San Andreas fault runs right through San Francisco Bay, and there are plenty of other active faults in the area.
128624
The transmission of the various modes of vibration of an earthquake to a building can depend on whether the building is constructed on solid rock or on sand or silt.  Sometimes the excavation for the building and refill can also alter the ground response.  Sand and silt can actually amplify the effects on a building and earthquakes can actually liquify soft ground under certain cirstances especially when very moist.  You may not be able to build a buffer into the ground to protect the building.  Instead it may be necessary to obtain seismologist's estimates of the worst expected earthquake g-loads for the area and a geologist's estimates on how the selected site will react.  With that information a building can be designed to withstand the site response to an earthquake with room to spare (factor of safety).  Good luck.
152237
Try this: http://www.piezo.com/index.html
460913
structures are subjected to 2 types of movement in an earthquake, P-wave and S-wave. P-wave is the sharp up and down movement, called the primary wave. S-wave is the longer lasting side to side movement, called secondary waves. then there are the after shocks. PBS NOVA has several well made documentaries about that stuff.
152030
Here is one from Seattle:\nhttp://www.classzone.com/books/earth_science/terc/content/visualizations/es1005/es1005page01.cfm?chapter_no=10\nHere is one on National Geographic:\nhttp://www.nationalgeographic.com/forcesofnature/interactive/index.html?section=e\nHere is one for sale on CD of the Loma Prieta earthquake:\nhttp://www.eeri.org/cds_publications/catalog/product_info.php?products_id=47\nHere is one of an earthquake in Tokyo in 2000:\nhttp://www.earthscape.org/t1/abc27/abc27.html\nHere is one from an anonymous contributor of the Pakistan earthquake:\nhttp://www.earthscape.org/t1/abc27/abc27.html\n\nProbably the best source is Google Video in beta. It has at least 127 earthquake videos on the site. \nGo here:\nhttp://video.google.com/videosearch?q=earthquake
816499
You won't be warned.  The earth will just start moving.  The danger isn't the earthquake.  The dangers are the things that fall on you, the fires that burn after (assuming gas lines or electricity or some source of fire and fuel).
138297
In general, the basis of a sensor is to measure some physical property (sound intensity, temperature, light intensity, position, velocity, acceleration, to name a few) and produce an electrical output that represents the amplitude of the property. There are sensors that don't output an electrical signal but indicate amplitude in some other way such as position. An example would be a mechanical speed governor. But the majority of sensors have an electrical output since we are able to do any needed amount of processing of such a signal.\nMicrophones and motion detectors are examples of acoustic sensors. Microphones generate an electric signal that is an analog of the sound it receives; i.e., the signal shows all the vibrations that make up the sound. This can be amplified and used to drive loudspeakers, recording equipment, etc. (If used to detect motion, this would be called "passive" detection.) Acoustic motion sensors use "active" detection. A very high-frequency loudspeaker sends out an ultrasonic sound signal, which results in a particular signal being reflected from nearby surfaces and returned to a microphone. With nothing in the sound field moving, the microphone receives the same sound frequency as is transmitted and a constant amplitude. A moving object reflects some of the sound back to the microphone at a slightly different frequency (due to the Doppler effect) and with slightly different amplitude due to the changing interference pattern created by the motion. Depending on the type of detector, the frequency and/or amplitude change triggers a detection signal, which then can be used to energize an alarm, open a door, turn on a light, etc.
3970
There is no reliable method to predict an earth quake.What scientists do is use mathematical models based on historical information of earth quakes and estimate the probability in different regions.Lasers and satellite based data and evaluations are used by some.
598797
seismographs and seismometers
481353
piezometer uses the piezoelectric electric effect.\nIf you compress a piece of quartz it produces a voltage.\nThis voltage is measured and displayed on a desired scale.\n\nUsually used to measure fluid pressure, so the voltmeter has a pressure scale printed on it.
642624
No, not a chance.\n\nThe frequency of Earthqakes is determined by the stress and strain along fault planes of which occur at plate boundries and pretty much anywhere there are rocks. The occurance of a earthquake is determined by the maximum stress at a given point along the fault plane. Some parts of the falut plane potentially are weaker than others. \n\nVolcanic activity is governed by the increase in pressure in the lava chamber,mechanical strength of the rock matter and the seperation of plates from each other. \n\nDrilling into the earths lithosphere does not increase the volumes of these two naturally occuring events. In terms of drilling, usually in the deeper section of the well the size of the hole is mainly 8 1/2" however can sometimes be smaller. During planning of the drilling it is very important to avoid hazards such as faults as they cause untold problems for the stability of the well. (We use a special type of mud to reduce the potential of the well collapsing) A typical well is approx 3000meters or 10000ish feet, however that does not mean to say that we are drilling the hole vertically, it also takes into account the horizontal distance drilled.\n\nFor my thesis in my final year at university, I studied the re-activation of ancient fault planes into recent sedimentary layers and also mapped the occurance of recorded faults in my study area. What I concluded from this study was that recent climatic events i.e the last ice age that swamped a large part of the northern hemispere, caused a massive strain in the earths crust due to 'ice loading'. The result of the removal of the ice saw the 're-bounding' of the earth - pretty much like if you squeeze a sponge it returns it shape. This phenoma is called isostatic rebound. However, the earth obviously is brittle unlike the sponge! \n\nThe sensisitivity of the instruments used in detecting earthquakes is the reason for most of the 'increased' activity in the last century.\n\nIn other words, nature is far more powerful than the average perosn who has not studied the earths process in detail can imagine!