Hanna Rhoads
Mrs. Medenica
7a Science
6/2/12
Earthquakes occur when the tectonic plates shift and draw back or push against each other. Earthquakes are seismic waves that travel on Earth’s surface away from the disturbance. There are foreshocks and aftershocks to all earthquakes, sometimes the aftershocks are stronger than the actual quake. So how do we know when an earthquake will occur and where? Every day there are many, many earthquakes, some days there are nearly 50 or more. Most are smaller ones and not much of a threat, but there are ways for scientists to monitor and predict where big earthquakes will occur. Earthquakes can cause faults and change in elevation, movement of the plates cause Mnt. Everest’s peak to rise by the year. Earthquakes can be very destructive destroying both manmade and natural creations. Scientists have developed different scales and ways of measuring the strength of an earthquake, some measure based on activity of the plates and others measure based on damage caused by it. Scientists have many ways of predicting, studying, and measuring earthquakes and the seismic waves that cause them.
Most earthquakes occur around the borders of the plates, the movement of the plates causes them. Depending on the type of boundaries between the plates, and how active they are; there is more chance of earthquakes and seismic activity in some places than in others. Scientists still cannot be completely accurate when predicting large quakes, especially when all some have to work with is the history of quakes in the past. Scientists have to understand how the plates are moving, movement of one plate can cause another neighboring plate to move so with the plates always moving and knocking into each other, scientists need to take into account past activity as well as recent activity. For example, the plates are moving in a certain way, the different boundaries show which way the plates are shifting. The movement of the plates causes earthquakes so along the borders of the most active plates, there will be the biggest and most frequent quakes. Although scientists can’t tell exactly when an earthquake will occur, some claim that before an earthquake a combination of things occur: gas seeping out of cracks in Earth’s crust, animals having weird behavior, also changes in magnetic fields are said to occur before an earthquake.
Scientists study earthquakes to be able to know why, when, where, and how strong they will be when they happen. One way of studying quakes is a seismograph, it is used to measure the movement and strength of an earthquake by measuring the tremors caused by the seismic waves. This allows scientists to measure the duration of the earthquake as well as they simply note when tremors start and stop. By knowing the difference of time between the primary and secondary waves, you can find the distance to the epicenter; by knowing the distance, you can use that from 3 locations to find the relative area where the epicenter of the quake is. Scientist know from studying the quakes that, the elevation and shape of landforms and whole land masses are changing. In these areas there is more frequent seismic activity, the movement of the plates is causing some mountains to grow yearly (Everest and the Himalayas), moving land masses make oceans and seas change size (Pacific, Atlantic, and Mediterranean), and land masses to split (Great Rift Valley, Iceland, etc.). The changes are very slow, but knowing they are happening also allows scientists the opportunity to study how movement of the plates like this will cause seismic activity.
There are many scales to measure earthquakes, one for instance is the Richter Scale. The Richter Scale is used to compare earthquakes. For example one earthquake could be a 1.0 and another a 4.9, each number is 10x larger than the one before it (1=10,2=100, etc.). A 1 on the scale is a relatively small earthquake but a 5 or 6 can cause minor damage and injury and is accompanied with decent shakes. Another way of measuring quakes is a ShakeMap, ShakeMaps are used to show where the shaking was felt and where it was most intense. By creating ShakeMaps you can estimate where help and repair will be needed most and work out from that. A ShakeMap uses the numbers 1(not felt) to above 10(extreme) to represent potential damage, strength of tremors, and estimated injuries/fatalities.
My findings, were that there are many ways that scientists can study, attempt to predict, and measure earthquakes. Earthquakes are hard to predict but scientists can get a general idea, seismographs and the tectonic plates are used to research seismic activity, and the Richter Scale and ShakeMaps are some of many ways to measure and show earthquakes affects. Scientists learn more and more about earthquakes, the tectonic, plates, and seismic activity every year. Their findings allow people to be prepared for the worst and strengthen our defenses.
Sources:
- HowStuffWorks.com/nature/natural-disasters/earthquake7
- science.HowStuffWorks.com/environmental/earth/geophysics/question142
Mrs. Medenica
7a Science
6/2/12
Earthquake Warning Systems Research Essay
Earthquakes occur when the tectonic plates shift and draw back or push against each other. Earthquakes are seismic waves that travel on Earth’s surface away from the disturbance. There are foreshocks and aftershocks to all earthquakes, sometimes the aftershocks are stronger than the actual quake. So how do we know when an earthquake will occur and where? Every day there are many, many earthquakes, some days there are nearly 50 or more. Most are smaller ones and not much of a threat, but there are ways for scientists to monitor and predict where big earthquakes will occur. Earthquakes can cause faults and change in elevation, movement of the plates cause Mnt. Everest’s peak to rise by the year. Earthquakes can be very destructive destroying both manmade and natural creations. Scientists have developed different scales and ways of measuring the strength of an earthquake, some measure based on activity of the plates and others measure based on damage caused by it. Scientists have many ways of predicting, studying, and measuring earthquakes and the seismic waves that cause them.
Most earthquakes occur around the borders of the plates, the movement of the plates causes them. Depending on the type of boundaries between the plates, and how active they are; there is more chance of earthquakes and seismic activity in some places than in others. Scientists still cannot be completely accurate when predicting large quakes, especially when all some have to work with is the history of quakes in the past. Scientists have to understand how the plates are moving, movement of one plate can cause another neighboring plate to move so with the plates always moving and knocking into each other, scientists need to take into account past activity as well as recent activity. For example, the plates are moving in a certain way, the different boundaries show which way the plates are shifting. The movement of the plates causes earthquakes so along the borders of the most active plates, there will be the biggest and most frequent quakes. Although scientists can’t tell exactly when an earthquake will occur, some claim that before an earthquake a combination of things occur: gas seeping out of cracks in Earth’s crust, animals having weird behavior, also changes in magnetic fields are said to occur before an earthquake.
Scientists study earthquakes to be able to know why, when, where, and how strong they will be when they happen. One way of studying quakes is a seismograph, it is used to measure the movement and strength of an earthquake by measuring the tremors caused by the seismic waves. This allows scientists to measure the duration of the earthquake as well as they simply note when tremors start and stop. By knowing the difference of time between the primary and secondary waves, you can find the distance to the epicenter; by knowing the distance, you can use that from 3 locations to find the relative area where the epicenter of the quake is. Scientist know from studying the quakes that, the elevation and shape of landforms and whole land masses are changing. In these areas there is more frequent seismic activity, the movement of the plates is causing some mountains to grow yearly (Everest and the Himalayas), moving land masses make oceans and seas change size (Pacific, Atlantic, and Mediterranean), and land masses to split (Great Rift Valley, Iceland, etc.). The changes are very slow, but knowing they are happening also allows scientists the opportunity to study how movement of the plates like this will cause seismic activity.
There are many scales to measure earthquakes, one for instance is the Richter Scale. The Richter Scale is used to compare earthquakes. For example one earthquake could be a 1.0 and another a 4.9, each number is 10x larger than the one before it (1=10,2=100, etc.). A 1 on the scale is a relatively small earthquake but a 5 or 6 can cause minor damage and injury and is accompanied with decent shakes. Another way of measuring quakes is a ShakeMap, ShakeMaps are used to show where the shaking was felt and where it was most intense. By creating ShakeMaps you can estimate where help and repair will be needed most and work out from that. A ShakeMap uses the numbers 1(not felt) to above 10(extreme) to represent potential damage, strength of tremors, and estimated injuries/fatalities.
My findings, were that there are many ways that scientists can study, attempt to predict, and measure earthquakes. Earthquakes are hard to predict but scientists can get a general idea, seismographs and the tectonic plates are used to research seismic activity, and the Richter Scale and ShakeMaps are some of many ways to measure and show earthquakes affects. Scientists learn more and more about earthquakes, the tectonic, plates, and seismic activity every year. Their findings allow people to be prepared for the worst and strengthen our defenses.
Sources:
- HowStuffWorks.com/nature/natural-disasters/earthquake7
- science.HowStuffWorks.com/environmental/earth/geophysics/question142
Well done Hanna. I love How Stuff Works! You included really good information here. How else are scientists able to predict Earthquakes or at least prevent damage?
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