Notes for Ch.2-3

Notes for Section 2-3

2/4/2011

Seismic waves cause the seismograph's drum to vibrate. But the suspended weight with the pen attached moves very little. Therefore, the pen stays in place and records the drum's vibrations.

Patterns called seismogram, is record of an earthquake's seismic waves produced by a seismograph.

To monitor faults, geologists have developed instruments to measure changes in elevation, tilting of the land surface, and ground movements along faults.

Tiltmeter measures tilting or raising of the ground

Creep meter uses a wire stretched across a fault to measure horizontal movement of the ground.

Laser-Ranging Device use a laser beam to detect horizontal fault movements

Scientists can monitor changes in elevation as well as horizontal movement along faults using a network of Earth-orbiting satellites called GPS, Global Positioning System was developed to help ships and planes find their routes

Seismographs and fault-monitoring devices provide data used to map faults and detect changes along faults. Geologists are also trying to use these data to develop a method of predicting earthquakes.

Mapping Faults: When seismic waves encounter a fault, the waves are reflected off the fault. Seismographs can detect these reflected seismic waves.

Friction is the force that opposes the motion of one surface as it moves across another surface. Friction exists because surfaces are not perfectly smooth.

Where friction along a fault is low, the rock on both sides of the fault slide by each other without much sticking.

Questions:

1. What is a seismograph?

Seismograph is an instrument which indicates the severe seismic waves/movement.

How does a seismograph record seismic waves?

Seismic waves cause the seismograph's drum to vibrate. When vibration occurs, scientists can notice the movement. A seismograph's heavy weight resists motion during a quake.

How would the seismograms for the two earthquakes compare?

The height of the jagged lines drawn on the seismograph's drum is greater for a more severe earthquake or for an earthquake close to the seismograph. This seismograph explains the difference of two earthquakes by giving the movements.

2 What four instruments are used to monitor faults?

The 4 major instruments are tilt-meters,

Creep meters,

Laser-ranging devices,

and GPS Satellites.

What changes does each instrument measure?

Tiltmeter measures tilting or rising of the ground

Creep meter uses a wire stretched across a fault to measure horizontal movement of the ground.

Laser-Ranging Device uses a laser beam to detect horizontal fault movements.

Scientists can monitor changes in elevation as well as horizontal movement along faults using a network of Earth-orbiting satellites called GPS, Global Positioning System was developed to help ships and planes find their routes

A satellite that monitors a fault detects an increasing tilt in the land surface along the fault. What could this change in the land surface indicate?

I assume that the seismograph detects an increasing tilt in land surface along the fault.

3. What are three ways in which geologists use seismographic data?

The three ways in geologists use to seismograph the data are map faults, develop method of prediction of earthquakes, and they detect the changes along faults

How do geologists use seismographic data?

Seismographs and fault-monitoring devices provide data used to map faults and detect changes along faults. Geologists are also trying to use these data to develop a method of predicting earthquakes.

Why do geologists collect data on friction along the sides of faults?

Geologists study the types of movement that occur along faults. How rocks move along a fault depends on how much friction there is between the sides of the fault.

More to Explore:

You have just located an earthquake's epicenter. Find this earthquake's location on the map of Earthquake Risk in the United States. What is the risk of earthquakes in the area of this quake?

What conclusions can you draw from this map about the cause of earthquakes in this area.

The earthquake's epicenter in the Map of America is just located South-West of Tennessee; as far as I know (I researched FEMA), Tennessee State is high risk or the earthquakes occurred there are high risk. In conclusion, I discovered that finding the earthquakes's epicenter is not "piece of cake," in-order to find the epicenter of the earthquakes, we should focus on difference between P and S waves. (The key to the epicenter result)

Write a paragraph explaining how measuring changes in the land, along a fault might help scientists to predict earthquakes. Scientists can discover and notice the hit of the "earthquakes," by measuring the changes in the land. Scientists utilize instruments such as the 4 major instruments tilt-meters,Creep meters, Laser-ranging devices, and GPS Satellites; Tiltmeter measures tilting or rising of the ground. Creep meter uses a wire stretched across a fault to measure horizontal movement of the ground.Laser-Ranging Device uses a laser beam to detect horizontal fault movements. Scientists can monitor changes in elevation as well as horizontal movement along faults using a network of Earth-orbiting satellites called GPS, Global Positioning System was developed to help ships and planes find their routes. By utilizing these materials to see and predict the earthquakes, scientists can discover where and how and when the earthquake is hitting and heading.

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