earthquakes!
DESCRIPTION
Earthquakes!. Earth is never still!. Every year there are 500,000 detectable earthquakes 100,000 of them can be felt Only 100 cause damage http://earthquake.usgs.gov/eqcenter/recenteqsww/. Ohio Earthquake Facts. Last earthquake occurred January 26, 2008 Magnitude 1.8 - PowerPoint PPT PresentationTRANSCRIPT
Earthquakes!Earthquakes!
Earth is never still!Earth is never still!
Every year there are 500,000 detectable earthquakes
100,000 of them can be felt
Only 100 cause damage
http://earthquake.usgs.gov/eqcenter/recenteqsww/
Every year there are 500,000 detectable earthquakes
100,000 of them can be felt
Only 100 cause damage
http://earthquake.usgs.gov/eqcenter/recenteqsww/
Ohio Earthquake FactsOhio Earthquake Facts
Last earthquake occurred January 26, 2008
Magnitude 1.8
Largest quake occurred March 9, 1937
Magnitude 5.4
Last earthquake occurred January 26, 2008
Magnitude 1.8
Largest quake occurred March 9, 1937
Magnitude 5.4
Causes of EarthquakesCauses of Earthquakes
All rocks have an elastic limit.
If the forces acting on these rocks exceed this limit or overcome friction between blocks, the crust snaps and an earthquake occurs.
This phenomenon is known as the elastic rebound theory.
All rocks have an elastic limit.
If the forces acting on these rocks exceed this limit or overcome friction between blocks, the crust snaps and an earthquake occurs.
This phenomenon is known as the elastic rebound theory.
Causes of EarthquakesCauses of Earthquakes
The most common cause of earthquakes is faulting.
The most common cause of earthquakes is faulting.
Causes of EarthquakesCauses of Earthquakes
As rocks slide past one another large amounts of energy that has been built up over time is finally released, causing an earthquake.
The point inside the Earth where rock first breaks or moves in called the focus of the earthquake.
As rocks slide past one another large amounts of energy that has been built up over time is finally released, causing an earthquake.
The point inside the Earth where rock first breaks or moves in called the focus of the earthquake.
Classifying EarthquakesClassifying Earthquakes
Shallow focus earthquakes originate between the Earth’s surface at a depth of 70 km.
Intermediate focus earthquakes originate between 70-300 km.
Deep focus earthquakes originate between 300-700 km.
Shallow focus earthquakes originate between the Earth’s surface at a depth of 70 km.
Intermediate focus earthquakes originate between 70-300 km.
Deep focus earthquakes originate between 300-700 km.
Classifying EarthquakesClassifying Earthquakes
Seismic WavesSeismic Waves
When an earthquake occurs, energy moves away from the focus in the forms of waves called seismic waves.
When an earthquake occurs, energy moves away from the focus in the forms of waves called seismic waves.
Seismic WavesSeismic Waves
Primary (P) waves are the fastest seismic waves.
They compress and expand like a slinky.
P waves can travel through solid and liquid rock.
Primary (P) waves are the fastest seismic waves.
They compress and expand like a slinky.
P waves can travel through solid and liquid rock.
Seismic WavesSeismic Waves
Secondary (S) waves are the second fastest seismic wave.
They vibrate up and down and side to side.
S waves can only travel through solid rock.
Secondary (S) waves are the second fastest seismic wave.
They vibrate up and down and side to side.
S waves can only travel through solid rock.
Seismic WavesSeismic WavesSurface (L)
waves are the slowest seismic waves.
L waves travel in a rolling motion along the surface of the Earth.
Surface (L) waves are the slowest seismic waves.
L waves travel in a rolling motion along the surface of the Earth.
Studying EarthquakesStudying Earthquakes
Scientists use sensitive instruments called seismographs to measure and record seismic waves.
The seismograph’s record of waves is called a seismogram.
A scientist who studies earthquakes is called a seismologist.
Scientists use sensitive instruments called seismographs to measure and record seismic waves.
The seismograph’s record of waves is called a seismogram.
A scientist who studies earthquakes is called a seismologist.
Studying EarthquakesStudying Earthquakes
Studying EarthquakesStudying Earthquakes
The epicenter is the place on the surface of the Earth directly above the focus of the earthquake.
The epicenter is the place on the surface of the Earth directly above the focus of the earthquake.
Studying EarthquakesStudying Earthquakes
Lag time is the difference between the arrival of the P and S waves.
Lag time is the difference between the arrival of the P and S waves.
Studying EarthquakesStudying Earthquakes
Seismologists need to take readings form 3 stations in order to locate the epicenter of an earthquake.
Seismologists need to take readings form 3 stations in order to locate the epicenter of an earthquake.
Studying EarthquakesStudying Earthquakes
1000 km
500 km
400 kmepicenter
Studying EarthquakesStudying Earthquakes
The magnitude of an earthquake is the total amount of energy released.
The magnitude of an earthquake is the total amount of energy released.
Studying EarthquakesStudying Earthquakes
The Richter scale is a logarithmic scale used to determine the strength of an earthquake (1-10) based on the energy that is released.
Humans cannot feel any earthquake activity lower than a 3.
Those that measure 6 or more are considered major earthquakes.
The strongest earthquake recorded occurred in Chile in 1960 and had a magnitude 9.5.
The Richter scale is a logarithmic scale used to determine the strength of an earthquake (1-10) based on the energy that is released.
Humans cannot feel any earthquake activity lower than a 3.
Those that measure 6 or more are considered major earthquakes.
The strongest earthquake recorded occurred in Chile in 1960 and had a magnitude 9.5.
Studying EarthquakesStudying Earthquakes
Studying EarthquakesStudying Earthquakes
The Mercalli scale is a method of describing describing the strength of an earthquake in terms of damage that is done to surrounding structures.
The measure of damage done by an earthquake is called intensity.
The Mercalli scale is a method of describing describing the strength of an earthquake in terms of damage that is done to surrounding structures.
The measure of damage done by an earthquake is called intensity.
Earthquake DamageEarthquake Damage The effect of an earthquake in a given region
depends greatly on the local surface and underground geologic conditions.
The effect of an earthquake in a given region depends greatly on the local surface and underground geologic conditions.
1985 Mexico City1985 Mexico City earthquakeearthquake
Earthquake DamageEarthquake Damage
Loss of human life during earthquakes is usually attributed to falling buildings and fires.
Loss of human life during earthquakes is usually attributed to falling buildings and fires.
1994 Northridge1994 Northridge earthquakeearthquake
Earthquake DamageEarthquake Damage
1906 San Francisco1906 San Francisco earthquakeearthquake
Earthquake DamageEarthquake Damage
1994 Northridge earthquake1994 Northridge earthquake
Earthquake DamageEarthquake Damage
Earthquakes also occur on the floor of the ocean, which often produce displacement of water called tsunami.
Tsunami can travel at speeds up to 700-800 km per hour and can reach heights of up to 20 meters - that is the height of a 6 story building!
Earthquakes also occur on the floor of the ocean, which often produce displacement of water called tsunami.
Tsunami can travel at speeds up to 700-800 km per hour and can reach heights of up to 20 meters - that is the height of a 6 story building!
Earthquake DamageEarthquake Damage
Earthquake DamageEarthquake Damage
2004 Indonesian tsunami2004 Indonesian tsunami
Earthquake DamageEarthquake Damage
2004 Indonesian Tsunami2004 Indonesian Tsunami