1a.) What is a seismograph?
A seismograph is a device used by scientists to record, monitor, and analyze movements of the earth. The average seismograph will consist of a weight attached to a frame by spring or wire. There is a pen or other writing device hanging down, stuck to the bottom of the weight. Its point rests on a rotating drum, which moves when seismic waves occur. There is a paper wrapped very tightly along the drum, and when it moves, the pen draws a line on it. When earthquakes hit the lab, the drum moves a lot, but the pen mostly stays still, and records the movements of the drum. Scientists can look at seismographs, and measure how much the earth is moving.
1b.) How does a seismograph record waves?
A seismograph records waves with its drum. The rotating drum will vibrate whenever it feels seismic activity. On the other hand, the pen is kept still by the weight it's attached to, so its inky tip records the movements of the vibrating drum. It's like moving paper to write letters instead of moving the pen.
1c.) A seismograph records a strong earthquake and a weak earthquake. How would the seismograms for the two earthquakes compare?
If a seismograph recorded a strong earthquake and then a weak one, the strong quake would have a much more turbulent and violent line, with many high points. The weak earthquake would make a less agitated line, with lower points. This is because when the strong earthquake hit, the rotating drum vibrated quite a lot, but since the pen stayed still, you can see exactly how much it moved; same with the smaller earthquake.
2a.) What four instruments are used to monitor faults?
The four instruments used to monitor faults are tilt-meters, creep meters, laser-ranging devices, and GPS satellites. Each instrument has its own way of measuring the movements of faults and the land around them.
2b.) What changes does each instrument measure?
Tilt meters measure the tilting of the ground (as could be expected). They are made of two liquid-filled bulbs connected by one hollow stem. When the land ascends, the liquid in one bulb pours into the other bulb, and vice versa. Creep meters consist of wire stretched across a fault, anchored to a post on one side, but attached to a sliding weight on the other. Scientists can tell how much the fault moved by how much the weight was moved. Laser-ranging devices use laser beams to detect movements in faults, and GPS satellites orbit earth and measure tiny movements of certain markers set up on both sides of a fault.
2c.) A satellite that monitors a fault detects an increasing tilt in the land surface along a fault. What could this change in the land surface indicate?
If there is an increasing tilt in the land surface along a fault, this could mean that an earthquake might soon occur. This is because stress is slowly building up in the area around this fault, and once too much stress builds up...KABOOM (rocks slip creating earthquakes). The type of stress building up would probably be compression, and possibly shearing. Not tension, because tension pulls rocks apart, but compression could definitely work, because it is caused by two plates pushing together, which can create mountains and volcanoes. In a thousand years, this spot of land that is pushing up might become a great mountain range.
3a.) What are three ways in which geologists use seismographic data?
Three ways that geologists use seismographic data is to map faults, monitor the changes along faults, and to try to predict earthquakes. Sometimes, it's hard to detect faults, because they are often covered with soil or rock, but when seismic waves hit faults, they bounce back, getting recorded on seismographs. Then, scientists can map them. Monitoring changes along faults can help predict earthquakes. If you can find out how much friction there is in a fault, you can tell whether or not there is a higher earthquake risk or not; if there is high friction, the rocks will get stuck, creating tension, that will be released in an earthquake. When there is low friction, the rocks will just slide by, and there is a very low possibility of an earthquake.
3b.) How do geologists use seismographic data to make maps of faults?
Geologists use seismographic data to make maps of faults when they aren't visible. Some faults are located under soil and rock, but when seismic waves hit them, they bounce back in reflection. Seismographs can record these reflections, and then geologists know that faults are there.
3c.) Why do geologists collect data on friction along the sides of faults?
Geologists collect data on friction along the sides of faults in order to figure out whether or not earthquakes might occur in certain places. If there is a very low amount of friction, the rocks on either side of the fault will slide by each other, and not stick at all, but if you have a very high amount of friction, the rocks will get stuck. If the rocks get stuck, then energy/tension will build up in the fault, and it will eventually be released in an earthquake.
A seismograph is a device used by scientists to record, monitor, and analyze movements of the earth. The average seismograph will consist of a weight attached to a frame by spring or wire. There is a pen or other writing device hanging down, stuck to the bottom of the weight. Its point rests on a rotating drum, which moves when seismic waves occur. There is a paper wrapped very tightly along the drum, and when it moves, the pen draws a line on it. When earthquakes hit the lab, the drum moves a lot, but the pen mostly stays still, and records the movements of the drum. Scientists can look at seismographs, and measure how much the earth is moving.
1b.) How does a seismograph record waves?
A seismograph records waves with its drum. The rotating drum will vibrate whenever it feels seismic activity. On the other hand, the pen is kept still by the weight it's attached to, so its inky tip records the movements of the vibrating drum. It's like moving paper to write letters instead of moving the pen.
1c.) A seismograph records a strong earthquake and a weak earthquake. How would the seismograms for the two earthquakes compare?
If a seismograph recorded a strong earthquake and then a weak one, the strong quake would have a much more turbulent and violent line, with many high points. The weak earthquake would make a less agitated line, with lower points. This is because when the strong earthquake hit, the rotating drum vibrated quite a lot, but since the pen stayed still, you can see exactly how much it moved; same with the smaller earthquake.
2a.) What four instruments are used to monitor faults?
The four instruments used to monitor faults are tilt-meters, creep meters, laser-ranging devices, and GPS satellites. Each instrument has its own way of measuring the movements of faults and the land around them.
2b.) What changes does each instrument measure?
Tilt meters measure the tilting of the ground (as could be expected). They are made of two liquid-filled bulbs connected by one hollow stem. When the land ascends, the liquid in one bulb pours into the other bulb, and vice versa. Creep meters consist of wire stretched across a fault, anchored to a post on one side, but attached to a sliding weight on the other. Scientists can tell how much the fault moved by how much the weight was moved. Laser-ranging devices use laser beams to detect movements in faults, and GPS satellites orbit earth and measure tiny movements of certain markers set up on both sides of a fault.
2c.) A satellite that monitors a fault detects an increasing tilt in the land surface along a fault. What could this change in the land surface indicate?
If there is an increasing tilt in the land surface along a fault, this could mean that an earthquake might soon occur. This is because stress is slowly building up in the area around this fault, and once too much stress builds up...KABOOM (rocks slip creating earthquakes). The type of stress building up would probably be compression, and possibly shearing. Not tension, because tension pulls rocks apart, but compression could definitely work, because it is caused by two plates pushing together, which can create mountains and volcanoes. In a thousand years, this spot of land that is pushing up might become a great mountain range.
3a.) What are three ways in which geologists use seismographic data?
Three ways that geologists use seismographic data is to map faults, monitor the changes along faults, and to try to predict earthquakes. Sometimes, it's hard to detect faults, because they are often covered with soil or rock, but when seismic waves hit faults, they bounce back, getting recorded on seismographs. Then, scientists can map them. Monitoring changes along faults can help predict earthquakes. If you can find out how much friction there is in a fault, you can tell whether or not there is a higher earthquake risk or not; if there is high friction, the rocks will get stuck, creating tension, that will be released in an earthquake. When there is low friction, the rocks will just slide by, and there is a very low possibility of an earthquake.
3b.) How do geologists use seismographic data to make maps of faults?
Geologists use seismographic data to make maps of faults when they aren't visible. Some faults are located under soil and rock, but when seismic waves hit them, they bounce back in reflection. Seismographs can record these reflections, and then geologists know that faults are there.
3c.) Why do geologists collect data on friction along the sides of faults?
Geologists collect data on friction along the sides of faults in order to figure out whether or not earthquakes might occur in certain places. If there is a very low amount of friction, the rocks on either side of the fault will slide by each other, and not stick at all, but if you have a very high amount of friction, the rocks will get stuck. If the rocks get stuck, then energy/tension will build up in the fault, and it will eventually be released in an earthquake.
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