12-2 Studying Earthquakes
Chapter 12- Section 2: Studying Earthquakes
Recording Earthquakes
Seismology- The study of earthquakes and seismic waves
Seismograph- An instrument that records vibrations in the ground
Consists of three different devices that sense and record motion
Vertical Motion of the ground
Horizontal Motion- East and West
Horizontal Motion- North and South Records motion by tracing wave shaped lines on paper Or translates it into electronic signals.
Seismogram- The tracing of earthquake motion by a seismograph. P waves are the fastest, and the first to be recorded
S waves are the second waves to be recorded
Surface waves are the slowest, and the last to be recorded B. Locating an Earthquake
Distance to an Epicenter- Scientists look at the arrival time of the P waves and S waves
The longer apart the time the two waves arrive, the farther away the earthquake is.
To locate the Epicenter- Scientists use computers and complex triangulations based on data from a few different seismographs.
Simpler (but less accurate) Method- Scientists made circles around about three seismograph stations that recorded the earthquake, where all the circles met would be the epicenter.
C. Earthquake Measurement
Scientists studying earthquakes are looking for the amount of energy released by an earthquake
Scientists study the amount of damage caused by the earthquake MAGNITUDE
Magnitude- The measure of the strength of an earthquake
Determined by measuring the amount of ground motion caused by the earthquake
Richter Scale (for Small Earthquakes)- measures the ground motion from an earthquake to find the earthquakes strength.
Moment Magnitude (for Large Earthquakes)- a measures earthquake strength based on size of the area, rigidity of the rocks, and the average distance the fault that moved, traveled.
Moment Magnitude is expressed by a number. Larger the number, stronger the Earthquake
INTENSITY
Intensity- A measure of the effects of an
Recording Earthquakes
Seismology- The study of earthquakes and seismic waves
Seismograph- An instrument that records vibrations in the ground
Consists of three different devices that sense and record motion
Vertical Motion of the ground
Horizontal Motion- East and West
Horizontal Motion- North and South Records motion by tracing wave shaped lines on paper Or translates it into electronic signals.
Seismogram- The tracing of earthquake motion by a seismograph. P waves are the fastest, and the first to be recorded
S waves are the second waves to be recorded
Surface waves are the slowest, and the last to be recorded B. Locating an Earthquake
Distance to an Epicenter- Scientists look at the arrival time of the P waves and S waves
The longer apart the time the two waves arrive, the farther away the earthquake is.
To locate the Epicenter- Scientists use computers and complex triangulations based on data from a few different seismographs.
Simpler (but less accurate) Method- Scientists made circles around about three seismograph stations that recorded the earthquake, where all the circles met would be the epicenter.
C. Earthquake Measurement
Scientists studying earthquakes are looking for the amount of energy released by an earthquake
Scientists study the amount of damage caused by the earthquake MAGNITUDE
Magnitude- The measure of the strength of an earthquake
Determined by measuring the amount of ground motion caused by the earthquake
Richter Scale (for Small Earthquakes)- measures the ground motion from an earthquake to find the earthquakes strength.
Moment Magnitude (for Large Earthquakes)- a measures earthquake strength based on size of the area, rigidity of the rocks, and the average distance the fault that moved, traveled.
Moment Magnitude is expressed by a number. Larger the number, stronger the Earthquake
INTENSITY
Intensity- A measure of the effects of an