EARTHQUAKES: WHY? AND HOW?. EARTHQUAKES Caused by plate tectonic stresses sudden movement or shaking of the Earth Located at plate boundaries Resulting.

Slides:

Advertisements

Similar presentations

Friday, March 23 nd 1 Attendance 2 Go over Review Sheet Test Pass Back papers.

Advertisements

Earth Science Chapter 5 Earthquakes.

4.2 Earthquakes & Seismic Waves. earthquakes - movements or shaking of the ground when rock (plates) move suddenly and release energy. aftershock – a.

Earthquakes What Is An Earthquake? Click here to find out.

Seismic waves and the shadow zone.  Sudden release of energy in the Earth’s crust and creates seismic waves. Occurs naturally or human induced.

Earthquakes Chapter 5. Earthquakes What causes and earthquake? 1._____________________________________ 2.Stress adds _________ to rock and ___________.

Earthquake Measurement

Earthquakes and Seismic Waves

EARTHQUAKES: WHY? AND HOW?. EARTHQUAKES Caused by plate tectonic stresses sudden movement or shaking of the Earth Located at plate boundaries Resulting.

EARTHQUAKES 2007 Japan quake.

8.2 Measuring Earthquakes

PHS Geography Department Physical Geography/Natural Disasters.

Earthquakes. What is an earthquake? Used to describe the sudden slip on a fault, and the resulting ground shaking and radiated seismic energy caused by.

EARTHQUAKES: WHY? AND HOW?. EARTHQUAKES Caused by plate tectonic stresses sudden movement or shaking of the Earth Located at plate boundaries Resulting.

What are Seismic Waves?. Types of Waves: Seismic Waves We will be covering: Body Waves Primary or p-wave Primary or p-wave –Compression wave Secondary.

Earthquake – A sudden release of stored energy. This energy has built up over long periods of time as a result of tectonic forces within the earth.

Inside Earth Chapter 2 Earthquakes 2.2 Earthquakes and Seismic Waves.

EARTHQUAKES sudden movement or shaking of the Earth sudden movement or shaking of the Earth Caused by:Caused by: –plate tectonic stresses (stick-slip)

 stress -a force that acts on rock to change its shape or volume. 3 Types of Stress  tension -pulls on crust, stretching rock so it becomes thinner.

Permian – 225 Million Years ago Triassic – 200 Million Years ago.

Earthquakes Sudden movement of surface when accumulated strain along opposing sides of a fault is suddenly released. Rock stretches and snaps.

Chapter 8 Earthquakes. I. What are Earthquakes? Seismology is the science devoted to studying earthquakes Most take place near the edges of tectonic plates.

Earthquakes. What is an Earthquake? Earthquake—the vibration of Earth produced by the rapid release of energy – Most often caused by slippage along a.

Chapter 19 Notes Earthquakes.

Aim: What are Earthquakes and their characteristics? I. Earthquakes – any vibrating, shaking, or rapid motion of Earth’s crust. A. Fault – zone of weakness.

EARTHQUAKES: WHY? AND HOW?. EARTHQUAKES Caused by plate tectonic stresses sudden movement or shaking of the Earth Located at plate boundaries Resulting.

EARTHQUAKES: WHY? AND HOW?. EARTHQUAKES Caused by plate tectonic stresses sudden movement or shaking of the Earth Located at plate boundaries Resulting.

Chapter 12 Earthquakes.

Earthquake Scales Richter vs. Mercalli. What is an earthquake? Earthquakes are the vibration of the earth as a result of a release of energy – Earthquakes.

How do scientists know the structure of the Earth? Rock samples (direct evidence) Seismic waves (indirect evidence) –Vibrations that travel through Earth.

Earthquake s Natural Hazards Pertaining to the Lithosphere.

1. What do seismologists use to determine when an earthquake started? A seismogram 2. How is the intensity of an earthquake determined? By the amount.

CAL LESSON CLASS - V SUB - EVS LESSON - WHEN THE EARTH SHOOK ! BY

Earthquakes. Earthquakes Earthquakes are vibrations of the ground (violent shaking motions) created by the sudden release of energy accumulating in deformed.

 As you travel inside of Earth, the temperature _________________.

Students know how to identify transverse and longitudinal waves in mechanical media such as springs, ropes, and the Earth (seismic waves).

Chapter 12 Earthquakes.

Faults & Earthquakes These can be either constructive or destructive forces 3 basic types of geologic forces 1. Tension: pulling force ← → 2. Compression:

What are earthquakes?.

What are earthquakes? Stresses in the crust cause rock to move suddenly The sudden movement causes vibrations that travel as waves inside the Earth and.

Measuring and Predicting Earthquakes

Earthquakes & Plate Tectonics

EARTHQUAKES: WHY? AND HOW?

Earthquakes Waves and Faults.

Earthquakes Vibration of Earth produced by the rapid release of energy.

Do First Questions: What mechanical layer of the Earth are plates made of? What mechanical layer of the Earth is moving causing the plates to move?

EARTHQUAKES: WHY? AND HOW?

EARTHQUAKES: WHY? AND HOW?

Do First Questions: What mechanical layer of the Earth are plates made of? What mechanical layer of the Earth is moving causing the plates to move?

Earthquakes Vocab.

EARTHQUAKES: WHY? AND HOW?

Modified from Liz LaRosa

EARTHQUAKES: WHY? AND HOW?

Unit 3: The Dynamic Earth

EARTHQUAKES: WHY? AND HOW?

Chapter 12 - Section 2 Measuring Earthquakes

Whole Lot of Shaking Going On

Chapter 5.2 Earthquakes and seismic waves

Presentation transcript:

EARTHQUAKES: WHY? AND HOW?

EARTHQUAKES Caused by plate tectonic stresses sudden movement or shaking of the Earth Located at plate boundaries Resulting in breakage of the Earth’s brittle crust

PLATE TECTONIC STRESSES faults (= cracks where plate sections are moving in different directions)Plate boundaries and faults (= cracks where plate sections are moving in different directions) cause friction as plates move Plates in a fault zone have STICK-SLIP motion –Periods of no movement (stick) and fast movement (slip) –Energy stored as plates stick, –Energy released as plates slip

EARTHQUAKE DAMAGE LandsidesLandsides Building damageBuilding damage LiquefactionLiquefactionLiquefaction

LIQUEFACTION Results in a loss of soil strength & the ability of the soil to support weight when a solid (sand and soil) becomes saturated with water and acts like a heavy liquid

EARTHQUAKE DAMAGE Most caused by SURFACE waves (arrive last)

EARTHQUAKE INTENSITY Modified Mercalli scaleModified Mercalli scale= measurement of damage to structures Modified Mercalli scale From I to XII (Roman numerals)From I to XII (Roman numerals) Descriptive, changes with distance from epicenterDescriptive, changes with distance from epicenter Can change from location to locationCan change from location to locationlocation What you need: Your senses!Your senses! measures damage to man-made structures at certain location

ISOSEISMIC MAPS Loma Prieta Earthquake 1989 Connects areas of with the same Modified Mercalli numberConnects areas of with the same Modified Mercalli number Areas are colored according to Modified Mercalli numberAreas are colored according to Modified Mercalli number show the distribution of intensities show the distribution of intensities

EARTHQUAKE WAVES FOCUS = place deep within the Earth and along the fault where rupture occursFOCUS = place deep within the Earth and along the fault where rupture occurs EPICENTER = geographic point on surface directly above focusEPICENTER = geographic point on surface directly above focus SEISMIC WAVESSEISMIC WAVES produced by the release of energySEISMIC WAVES SEISMIC WAVES –move out in circles from the point of rupture (focus) –2 types: surface & body (travel inside & through earth’s layers) P waves: back and forth movement of rock; travel thru solid, liquid, gas S waves: sideways movement of rock; travel thru solids only

EARTHQUAKE WAVES Seismographs record earthquake waves Seismograms show: Amplitude of seismic waves (how much rock moves or vibrates)Amplitude of seismic waves (how much rock moves or vibrates) Distance to the epicenterDistance to the epicenter Earthquake directionEarthquake direction

EARTHQUAKE WAVES 3 types of seismic waves show up on seismogram3 types of seismic waves show up on seismogram –P waves: shake earth in same direction as wave; travel thru solid, liquid, gas –S waves: Shake earth sideways to wave direction; travel thru solids only –Surface waves: circular movement of rock; travel on surface – cause most damage!!

EARTHQUAKE WAVES P waves move through solids & liquids S waves move through solids only!!!

EARTHQUAKE WAVES Body P wavesS waves waves AKA Moves through Movement of rock Primary (1st to arrive) Longitudinal, Compression all states of matter (solid, liquid, gas) back and forth movement of rock push/pull or compression/stretch out Like slinky down stairs Vibration is same as the direction of travel Secondary (2nd to arrive - larger) Transverse, Shear Can go through solids only Move sideways perpendicular to direction of wave travel Like snake

EARTHQUAKE WAVES Lets test your understanding!! Is this a P or an S wave? P wave! S Wave

EARTHQUAKE MAGNITUDE measures the size of seismic waves  the energy released by the earthquake measures the size of seismic waves  the energy released by the earthquake Richter scale=measurement of energy released based upon wave amplitude (size of vibration) <2 to ~10<2 to ~10 Amplitude of wave goes up by 10 (Logarithmic scale)Amplitude of wave goes up by 10 (Logarithmic scale) What you need: Amplitude (size of vibration = wave height)Amplitude (size of vibration = wave height) Time between arrival of 1 st P and 1 st S wavesTime between arrival of 1 st P and 1 st S waves

HOW TO READ SEISMOGRAMS P & S (body waves) move through earth & arrive first P & S waves used to calculate magnitude of earthquake Amplitude = height of wave (how much the rock moves; size of vibration)

MERCALLI VS. RICHTER