EARTHQUAKESEARTHQUAKES earthquakesearthquakes = shaking of earth’s crust caused by a = shaking of earth’s crust caused by a

release of energyrelease of energy1. results from sudden movement of part of earth’s 1. results from sudden movement of part of earth’s crustcrust2. rocks under stress suddenly shift along a 2. rocks under stress suddenly shift along a faultfault = = break in break in lithospheric plate where movement can occurlithospheric plate where movement can occur3. friction can prevent rocks from moving for a time 3. friction can prevent rocks from moving for a time →→ fault is fault is said to be “locked”said to be “locked”4. most common cause is faulting4. most common cause is faulting

elastic rebound theoryelastic rebound theory = rocks that are strained past certain = rocks that are strained past certain point will fracture and spring back to original shapepoint will fracture and spring back to original shape

1. when rocks slip to new position seismic waves are released1. when rocks slip to new position seismic waves are released2. this energy can often cause stress in other rocks causing 2. this energy can often cause stress in other rocks causing

those to movethose to move

3. 3. aftershocksaftershocks = series of smaller earthquakes = series of smaller earthquakes originating originating close to focus of large earthquakesclose to focus of large earthquakes

a. large earthquakes can have as many as 1000 per a. large earthquakes can have as many as 1000 per dayday

b. frequency usually diminishes over timeb. frequency usually diminishes over time c. can cause damage to buildings and other structure, c. can cause damage to buildings and other structure,

especially if already weakenespecially if already weaken

Haiti

stressstress = force that causes pressure in rocks of crust = force that causes pressure in rocks of crust1. caused by isostatic adjustment and plate movement1. caused by isostatic adjustment and plate movement2. 2. strainstrain = change in shape or volume of rocks due to = change in shape or volume of rocks due to

stress stress of being squeezed, twisted, or pulled apartof being squeezed, twisted, or pulled apart3. three main types:3. three main types: a. a. compressioncompression = crustal rocks are squeezed together = crustal rocks are squeezed together 1) reduces volume of rock1) reduces volume of rock 2) tends to push rocks higher up or deeper down into 2) tends to push rocks higher up or deeper down into

crust crust 3) rock layers are thicker and shorter3) rock layers are thicker and shorter

b. b. tensiontension = force that pulls rocks apart = force that pulls rocks apart 1) rocks tend to become thinner and longer1) rocks tend to become thinner and longer 2) can cause fractures2) can cause fractures

c. c. shearingshearing = pushes rocks in opposite horizontal = pushes rocks in opposite horizontal directionsdirections

1) rocks bend, twist, or break apart as slide past each 1) rocks bend, twist, or break apart as slide past each otherother

2) tends to distort shape of rocks, 2) tends to distort shape of rocks, especially along plane especially along plane

between opposing forcesbetween opposing forces

4. 4. ductile deformationductile deformation = permanent deformation that occurs = permanent deformation that occurs when stress exceeds a certain when stress exceeds a certain

valuevalue a. material stay deformed even if stress is reduced to zeroa. material stay deformed even if stress is reduced to zero b. when stress exceeds strength of material, material b. when stress exceeds strength of material, material breaks or failsbreaks or fails c. rocks can become ductile at higher temperatures at c. rocks can become ductile at higher temperatures at

greater depths in crustgreater depths in crust

foldingfolding = permanent deformation or bending of a = permanent deformation or bending of a rock rock under stressunder stress

1. cracks may appear but rock layer is intact1. cracks may appear but rock layer is intact2. 2. foldsfolds = wavelike structures in rock layers = wavelike structures in rock layers a. vary greatly in sizea. vary greatly in size b. layered rocks with large folds often have b. layered rocks with large folds often have

smaller folds smaller folds within within the layersthe layersEx: Appalachian MountainsEx: Appalachian Mountains

c. c. limbslimbs = two sides of a fold = two sides of a fold d. d. strikestrike = compass direction of fold or of rock = compass direction of fold or of rock

layers layers exposed at surface along exposed at surface along foldfold

3. general types of folds:3. general types of folds: a. a. anticlineanticline = upward fold in layers = upward fold in layers 1) usually form a ridge1) usually form a ridge b. b. synclinesyncline = downward folds in layers = downward folds in layers 1) usually form valleys1) usually form valleys c. c. monoclinemonocline = gently dipping bends in horizontal = gently dipping bends in horizontal

rock rock layerslayers

focusfocus = actual point on fault where rocks break and = actual point on fault where rocks break and movemove

1. underground point of origin1. underground point of origin2. seismic waves energy travel outward in all directions2. seismic waves energy travel outward in all directions3. 3. shallow-focus earthquakesshallow-focus earthquakes = occur within 70 km of = occur within 70 km of

earth’s surfaceearth’s surface a. 90% of continental earthquakesa. 90% of continental earthquakes b. usually cause most damageb. usually cause most damage c. usually at divergent boundaries or transform c. usually at divergent boundaries or transform

boundariesboundaries

4. 4. intermediate-focus earthquakesintermediate-focus earthquakes = occur at depths = occur at depths between between 70 km and 70 km and 300 km 300 km

5. 5. deep-focus earthquakesdeep-focus earthquakes = occur at depths between = occur at depths between 300 km 300 km and 700 km and 700 km

a. occur at subduction zonesa. occur at subduction zones b. usually occur farther inlandb. usually occur farther inland6. factors into EQ intensity6. factors into EQ intensity

epicenterepicenter = point on surface directly above focus = point on surface directly above focus1. most violent shaking in this area1. most violent shaking in this area2. see greatest damage here2. see greatest damage here

Categories of breaks of rocks:Categories of breaks of rocks:1. 1. faultfault = when rocks do move along break = when rocks do move along break a. a. fault planefault plane = surface of a fault = surface of a fault b. b. hanging wallhanging wall = rocks above a normal fault = rocks above a normal fault

planeplane c. c. footwallfootwall = rocks below a normal fault plane = rocks below a normal fault plane

2. 2. jointsjoints = breaks along which no apparent = breaks along which no apparent movement has movement has occurred occurred

a. result of same stresses that lift, tilt, and fold a. result of same stresses that lift, tilt, and fold rock rock

layers into mountainslayers into mountains b. surface is usually a plane although some can be b. surface is usually a plane although some can be curvedcurved c. joint plane appears as a line on surface of rock c. joint plane appears as a line on surface of rock outcropoutcrop d. d. joint setsjoint sets = parallel groups of lines = parallel groups of lines e. provide channels through e. provide channels through which fluids enter and which fluids enter and move through bedrockmove through bedrock

TYPES OF FAULTSTYPES OF FAULTS1. 1. normal faultsnormal faults = hanging wall drops in relation to foot = hanging wall drops in relation to foot

wallwall a. caused by tension (pulling crust apart) a. caused by tension (pulling crust apart) b. fault plane at a steep angle or almost verticalb. fault plane at a steep angle or almost vertical c. form fault-blocked mountainsc. form fault-blocked mountains d. occur at divergent plate boundariesd. occur at divergent plate boundaries

Ex: Sierra NevadasEx: Sierra Nevadas Great Rift Valley of East AfricaGreat Rift Valley of East Africa

2. 2. reverse faultsreverse faults = hanging wall moves up in = hanging wall moves up in relation to relation to foot wallfoot wall

a. caused by compression (plates collide)a. caused by compression (plates collide) b. fault plane is steep or nearly verticalb. fault plane is steep or nearly vertical c. causes rocks to bend and sometimes breakc. causes rocks to bend and sometimes break d. occurs at convergent plate boundariesd. occurs at convergent plate boundaries

Ex: Himalayan MountainsEx: Himalayan Mountains

3. 3. thrust faultthrust fault = hanging wall moves up and slides over = hanging wall moves up and slides over foot foot wall wall

a. special type of reverse fault in which fault plane a. special type of reverse fault in which fault plane dips 45dips 45oo or or less from horizontalless from horizontal

b. caused by compressionb. caused by compression c. fault plane at low angle or nearly horizontal c. fault plane at low angle or nearly horizontal d. older rocks are pushed up on top of younger rocksd. older rocks are pushed up on top of younger rocks e. occur at convergent plate boundariese. occur at convergent plate boundaries

Ex: Glacier National Park mountainsEx: Glacier National Park mountains Rockies and AlpsRockies and Alps

4. 4. strike-slip faultsstrike-slip faults = rock on either side of fault plane = rock on either side of fault plane slides slides horizontally past each horizontally past each other other

a. caused by shearinga. caused by shearing b. hanging wall moves parallel to the foot wall but in b. hanging wall moves parallel to the foot wall but in

the the opposite directionopposite direction 1) each wall moves in opposite directions1) each wall moves in opposite directions 2) wall can move in same direction but at different 2) wall can move in same direction but at different

ratesrates c. move past each other without much upward or c. move past each other without much upward or

downward movementdownward movement d. occur at transform fault boundariesd. occur at transform fault boundaries

Ex: San Andreas Fault of CaliforniaEx: San Andreas Fault of California

Major Earthquake ZonesMajor Earthquake Zones1. along or near edges of the earth’s plates1. along or near edges of the earth’s plates2. three major areas:2. three major areas: a. a. Pacific Ring of FirePacific Ring of Fire = includes west coasts of = includes west coasts of

North and North and South America, east coast of Asia, South America, east coast of Asia, western Pacific western Pacific islands of Philippines, Indonesia, islands of Philippines, Indonesia, New Guinea, and New New Guinea, and New ZealandZealand

1) 80% occur along the edges of the Pacific plate1) 80% occur along the edges of the Pacific plate 2) called the 2) called the Circum-Pacific beltCircum-Pacific belt b. along mid-ocean ridges b. along mid-ocean ridges c. c. Mediterranean-Asian beltMediterranean-Asian belt = crosses southern = crosses southern

Europe & Europe & Asia (15% of activity)Asia (15% of activity)

3. 3. fault zonesfault zones = groups of interconnected faults = groups of interconnected faults a. form at plate boundariesa. form at plate boundaries b. movement could occur along one or more of the b. movement could occur along one or more of the

individual faultsindividual faults4. not all result from movement along plate 4. not all result from movement along plate boundariesboundaries a. can occur in the middle of a continenta. can occur in the middle of a continent b. due to ancient fault zone deep within earth’s crustb. due to ancient fault zone deep within earth’s crust

Ex: New Madrid, MissouriEx: New Madrid, Missouri

TYPES OF SEISMIC WAVESTYPES OF SEISMIC WAVES1. 1. body wavesbody waves = waves that travel from focus through = waves that travel from focus through

EarthEarth a. each earthquake produces two types: P & S a. each earthquake produces two types: P & S

waveswaves2. 2. primary wavesprimary waves = P wave = P wave (compressional waves) (compressional waves) a. travel fastest, squeeze and stretch rock materials a. travel fastest, squeeze and stretch rock materials

as pass as pass throughthrough

b. particles move back and forth in direction waves b. particles move back and forth in direction waves are are movingmoving

c. denser the material, faster c. denser the material, faster wave travelswave travels

d. can move through solids, d. can move through solids, liquids, or gasesliquids, or gases

3. 3. secondary wavessecondary waves = S waves = S waves (shear waves)(shear waves) a. arrive after P wavesa. arrive after P waves b. can travel through solids but not liquids or gases, b. can travel through solids but not liquids or gases,

not not always recorded at all locationsalways recorded at all locations c. speed up through denser materialc. speed up through denser material d. travel little more than half the speed of P waves d. travel little more than half the speed of P waves through solidsthrough solids e. particles move at right angles to direction of wavee. particles move at right angles to direction of wave

4. 4. surface wavessurface waves = L waves = L waves [long][long] a. slowest moving wave & travel along Earth’s a. slowest moving wave & travel along Earth’s

surfacesurface b. originate on surface at epicenterb. originate on surface at epicenter c. causes surface to moves up and down like an c. causes surface to moves up and down like an

ocean waveocean wave d. results in most damage since it bends and twists d. results in most damage since it bends and twists

surfacesurface (most destructive when travels through loose (most destructive when travels through loose

earth)earth)

e. two types:e. two types: 1) 1) Love wavesLove waves = cause particles of material to = cause particles of material to

move from side to side, in a direction move from side to side, in a direction perpendicular to waves’ direction of travelperpendicular to waves’ direction of travel

2) 2) Rayleigh wavesRayleigh waves = cause particles of material = cause particles of material to move in elliptical patterns, travel more to move in elliptical patterns, travel more slowly than Love wavesslowly than Love waves

Recording EarthquakesRecording Earthquakes1. 1. seismologistseismologist = scientist that studies earthquakes = scientist that studies earthquakes

and seismic wavesand seismic waves2. 2. seismology seismology = study of earthquake waves= study of earthquake waves3. 3. seismographseismograph (seismometers) = instrument that (seismometers) = instrument that

detects and detects and measure seismic wavesmeasure seismic waves a. developed by John Milne in 1893a. developed by John Milne in 1893 b. has three separate sensing devicesb. has three separate sensing devices 1) one records vertical motion of ground1) one records vertical motion of ground 2) other two record horizontal 2) other two record horizontal

motion in east-west and motion in east-west and north-south directionsnorth-south directions

c. records motion by c. records motion by 1) tracing wave shaped lines on paper or1) tracing wave shaped lines on paper or 2) translating motion into electronic signals2) translating motion into electronic signals d. distance pen departs from center line is related to d. distance pen departs from center line is related to

amount amount of energy released of energy released

4. 4. seismogramseismogram = seismograph record of waves on paper = seismograph record of waves on paper a. first major zigzag marks arrival of P waves at stationa. first major zigzag marks arrival of P waves at station b. slower S waves arrive next producing a different b. slower S waves arrive next producing a different

patternpattern

Structure of EarthStructure of Earth1. 1. inner coreinner core = solid, innermost layer = solid, innermost layer a. composed of very dense iron and nickela. composed of very dense iron and nickel b. temperature reaches approximately 5000b. temperature reaches approximately 5000ooCC c. very high pressurec. very high pressure d. begins about 5150 km below surfaced. begins about 5150 km below surface e. dense iron causes the existence of a magnetic e. dense iron causes the existence of a magnetic field around earth = field around earth = magnetospheremagnetosphere

2. 2. outer coreouter core = surrounds the inner core = surrounds the inner core a. composed of molten liquid iron and nickela. composed of molten liquid iron and nickel b. begins approximately 2900 km below surfaceb. begins approximately 2900 km below surface c. temperature range: 2000c. temperature range: 2000ooC to 5000C to 5000ooCC

3. 3. mantlemantle = layer that lies above outer core; divided into = layer that lies above outer core; divided into upper upper mantle and lower mantlemantle and lower mantle

a. largest layer = 80% of earth’s volume; 68% of earth’s a. largest layer = 80% of earth’s volume; 68% of earth’s massmass

b. density, temperature, and pressure increases with b. density, temperature, and pressure increases with depthdepth

c. temperature range = 870c. temperature range = 870ooC to 2200C to 2200ooCC d. d. MohoMoho (Mohorovic discontinuity) = boundary between (Mohorovic discontinuity) = boundary between

crust and upper mantlecrust and upper mantle 1) denser layer of lithosphere, will cause seismic 1) denser layer of lithosphere, will cause seismic

waves to waves to speed up speed up 2) 32 km below continents and 2) 32 km below continents and

5-10 km below ocean5-10 km below ocean

e. compose of mostly silicon, oxygen, iron, and e. compose of mostly silicon, oxygen, iron, and magnesium; has plasticitymagnesium; has plasticity

f. f. transition zonetransition zone = region in middle of mantle = region in middle of mantle 1) area where seismic wave velocities increase more 1) area where seismic wave velocities increase more

quickly quickly than expectedthan expected 2) separates upper mantle from denser lower mantle2) separates upper mantle from denser lower mantle

4. 4. crustcrust = outermost layer (thin) = outermost layer (thin) a. varies in thickness from 60 km in a. varies in thickness from 60 km in

mountainous mountainous regions to 5 km in oceanic regionsregions to 5 km in oceanic regions b. made of three types of solid rock = igneous, b. made of three types of solid rock = igneous,

sedimentary, and metamorphicsedimentary, and metamorphic

c. oceanic crust = beneath oceanc. oceanic crust = beneath ocean 1) mostly silicon, oxygen, iron, and magnesium1) mostly silicon, oxygen, iron, and magnesium 2) composition determined by samples taken from 2) composition determined by samples taken from

ocean ocean floor by deep sea drilling ship Glomar Challengerfloor by deep sea drilling ship Glomar Challenger

d. continental crust = beneath continentsd. continental crust = beneath continents 1) mostly silicon, oxygen, aluminum, calcium, 1) mostly silicon, oxygen, aluminum, calcium,

sodium, and sodium, and potassiumpotassium

2) average thickness is about 32 km2) average thickness is about 32 km

EARTHQUAKE MEASUREMENTEARTHQUAKE MEASUREMENT1. 1. magnitudemagnitude = measure of energy released = measure of energy released a. higher the wavy lines on seismogram, stronger a. higher the wavy lines on seismogram, stronger

the the earthquakeearthquake b. height of the tallest wavy line is used to b. height of the tallest wavy line is used to

calculate the calculate the strength of the quakestrength of the quake

c. c. Richter ScaleRichter Scale = used to describe earthquake = used to describe earthquake magnitudesmagnitudes

1) developed by Charles Richter in 19351) developed by Charles Richter in 1935 2) based on size of largest seismic waves generated2) based on size of largest seismic waves generated 3) each successive number increase in scale 3) each successive number increase in scale

represents represents increase in seismic-wave, increase in seismic-wave, or amplitude, of a or amplitude, of a

factor of 10factor of 10 4) each increase in 4) each increase in

magnitude represents magnitude represents about a 32-fold about a 32-fold increase in energyincrease in energy

d. d. moment magnitude scalemoment magnitude scale = includes size of fault = includes size of fault rupture, rupture, amount of movement along fault, and amount of movement along fault, and rock’s stiffnessrock’s stiffness

1) estimated from size of several types of seismic 1) estimated from size of several types of seismic waveswaves

e. largest EQ so far = 9.6e. largest EQ so far = 9.6 1) major EQ (widespread damage) = 7 or above1) major EQ (widespread damage) = 7 or above 2) moderate EQ = between 6 and 72) moderate EQ = between 6 and 7 3) minor EQ = between 2.5 and 63) minor EQ = between 2.5 and 6 4) 4) microquakesmicroquakes = =

less than 2.5 less than 2.5 (not usually (not usually felt by people)felt by people)

2. 2. intensityintensity = amount of damage caused to structures = amount of damage caused to structures a. modified a. modified Mercalli scaleMercalli scale = expresses intensity = expresses intensity

using Roman using Roman numeral and descriptionnumeral and description b. rating of I has low intensity where rating of XII is b. rating of I has low intensity where rating of XII is

total total destructiondestruction c. higher the number, the worse the damagec. higher the number, the worse the damage d. depends primarily on d. depends primarily on

amplitude of surface amplitude of surface waves generatedwaves generated

e. will decrease as e. will decrease as distance away from distance away from epicenter increasesepicenter increases

shadow zoneshadow zone = area on Earth between 105 = area on Earth between 105oo and 140 and 140oo from from focus focus

1. no seismic waves are detected1. no seismic waves are detected2. secondary waves are stopped by liquid outer core2. secondary waves are stopped by liquid outer core3. primary waves are slowed and deflected3. primary waves are slowed and deflected4. boundaries between 4. boundaries between

layers in Earth not only layers in Earth not only cause waves to change cause waves to change in speed, but also causes in speed, but also causes waves to bend.waves to bend.

LOCATING AN EARTHQUAKELOCATING AN EARTHQUAKE1. to assess how powerful an earthquake is, scientists 1. to assess how powerful an earthquake is, scientists

must determine distance of its epicenter from must determine distance of its epicenter from seismograph stationseismograph station

2. analyze difference between arrival times of P and S 2. analyze difference between arrival times of P and S waves on travel-time curveswaves on travel-time curves

a. P waves travel 1.7 times faster than S wavesa. P waves travel 1.7 times faster than S waves b. farther apart waves when measured, farther away b. farther apart waves when measured, farther away

epicenter is epicenter is

c. plot difference between arrival times of two c. plot difference between arrival times of two waves to determine how far earthquake is from waves to determine how far earthquake is from stationstation

d. measuring separation on seismogram or travel-d. measuring separation on seismogram or travel-time graph at which P-curve and S-curve have time graph at which P-curve and S-curve have same separation same separation →→ distance to epicenter can be distance to epicenter can be determined = determined = epicentral distanceepicentral distance

3. locating epicenter3. locating epicenter a. need information from at least three a. need information from at least three

seismograph seismograph stations at different locationsstations at different locations b. circle is drawn around each station on a mapb. circle is drawn around each station on a map c. radius of each circle equals that station’s c. radius of each circle equals that station’s

distance from distance from epicenterepicenter d. point where all three circles intersect is d. point where all three circles intersect is

location of location of epicenterepicenter4. time of occurrence is determined4. time of occurrence is determined

from travel-time graph by from travel-time graph by subtracting appropriate travel time subtracting appropriate travel time from known arrival time of wavefrom known arrival time of wave

EARTHQUAKES DAMAGEEARTHQUAKES DAMAGE1. factors that determine amount of damage caused1. factors that determine amount of damage caused a. strength of earthquake & how long shaking occursa. strength of earthquake & how long shaking occurs b. kind of rock and soil that underlies an areab. kind of rock and soil that underlies an area c. population of areac. population of area d. kinds of buildings in an aread. kinds of buildings in an area e. time at which e. time at which

it occursit occurs2. safer in an open, 2. safer in an open, level fieldlevel field

3. dangers:3. dangers: a. collapsed buildings and structuresa. collapsed buildings and structures b. from falling objects and flying glassb. from falling objects and flying glass c. landslides caused by soil c. landslides caused by soil liquefactionliquefaction = loose soil = loose soil

temporarily takes on properties of liquidtemporarily takes on properties of liquid 1) soft materials will amplify seismic waves1) soft materials will amplify seismic waves 2) can also cause foundation failures2) can also cause foundation failures d. fires, explosions caused by broken electric and d. fires, explosions caused by broken electric and

gas linesgas lines e. floodwaters released e. floodwaters released from collapsing damsfrom collapsing dams

Liquefaction of soil

4. destruction to buildings and property4. destruction to buildings and property a. not designed to withstand swaying motiona. not designed to withstand swaying motion b. type of ground beneath affects way building b. type of ground beneath affects way building

respondsresponds 1) loose soil and rock cause to sway violently1) loose soil and rock cause to sway violently 2) will cause bottom layers to collapse while top 2) will cause bottom layers to collapse while top

layers layers fall on top = “ fall on top = “pancakingpancaking”” c. c. fault scarpsfault scarps = areas of great vertical offset = areas of great vertical offset

produced due produced due to fault movementto fault movement

5. 5. tsunamistsunamis = giant ocean waves [also called = giant ocean waves [also called tidal waves]tidal waves] a. caused by two events related to undersea a. caused by two events related to undersea

earthquakesearthquakes 1) faulting - cause sudden drop or rise in ocean floor1) faulting - cause sudden drop or rise in ocean floor 2) underwater landslides - water above is thrown into 2) underwater landslides - water above is thrown into

up up and down motion and down motion b. can travel at speeds of 500 to 800 km/hrb. can travel at speeds of 500 to 800 km/hr c. when reach coast, crest can be as high as 30mc. when reach coast, crest can be as high as 30m d. cause great destruction and loss of lifed. cause great destruction and loss of life

e. e. Seismic Sea Wave Warning SystemSeismic Sea Wave Warning System (SSWWS) (SSWWS) 1) network of seismograph station around and in 1) network of seismograph station around and in

Pacific OceanPacific Ocean 2) alerts to location and magnitude of earthquake2) alerts to location and magnitude of earthquake 3) if tsunami possible will estimate arrival times at 3) if tsunami possible will estimate arrival times at

different locationsdifferent locations 4) warnings are issued to these areas immediately4) warnings are issued to these areas immediately 5) those near epicenter5) those near epicenter

will not have enough will not have enough time time

Earthquake Safety:Earthquake Safety:1. can occur in any region of United States1. can occur in any region of United States2. study the earthquake history of a region2. study the earthquake history of a region3. if an area has had them in the past you can 3. if an area has had them in the past you can

expect them in the futureexpect them in the future

4. before occurs, be prepared4. before occurs, be prepared a. make your home as safe as possiblea. make your home as safe as possible 1) take heavy objects down from high shelves and 1) take heavy objects down from high shelves and

place on lower shelvesplace on lower shelves 2) make sure hot water heaters and gas appliances 2) make sure hot water heaters and gas appliances

are are held securely to prevent broken gas linesheld securely to prevent broken gas lines

3) learn how to turn off gas, water, and electricity3) learn how to turn off gas, water, and electricity 4) keep on hand a supply of canned food, bottled 4) keep on hand a supply of canned food, bottled

water, flashlights, batteries, and portable radiowater, flashlights, batteries, and portable radio b. plan what to do if your are at home, school, work, or b. plan what to do if your are at home, school, work, or

in a carin a car

5. during, stay calm5. during, stay calm a. keep away from windows, heavy furniture, and a. keep away from windows, heavy furniture, and

other other objects that may fallobjects that may fall b. stand in doorway or crouch under desk or table to b. stand in doorway or crouch under desk or table to

protect protect yourselfyourself c. do not run outsidec. do not run outside d. if in a car stop in a place away from tall buildings, d. if in a car stop in a place away from tall buildings,

tunnels, power lines and bridgestunnels, power lines and bridges 1) remain in car 1) remain in car

until tremors stopuntil tremors stop

6. after, be cautious6. after, be cautious a. check for fires and fire hazardsa. check for fires and fire hazards b. stay clear of rubble that could contain many b. stay clear of rubble that could contain many

sharp edgessharp edges c. wear shoes when walking among broken glassc. wear shoes when walking among broken glass d. avoid downed power lines and objects touched d. avoid downed power lines and objects touched

by downed wiresby downed wires

Earthquake PreparationEarthquake Preparation1. most loss of life occurs when people are trapped in 1. most loss of life occurs when people are trapped in

and on crumbling structuresand on crumbling structures2. 2. seismic-safe structuresseismic-safe structures = resistant to vibrations that = resistant to vibrations that

occuroccur3. highways have cement pillars with reinforcing rods 3. highways have cement pillars with reinforcing rods

wrapped around themwrapped around them4. new buildings are anchored to 4. new buildings are anchored to

flexible, circular moorings made flexible, circular moorings made of steel plates filled with of steel plates filled with alternating layers of rubber and alternating layers of rubber and

steel allowing building to swaysteel allowing building to sway5. underground water and gas pipes 5. underground water and gas pipes should be replaced with ones that should be replaced with ones that will bend and not breakwill bend and not break

Earthquake Warnings and PredictionsEarthquake Warnings and Predictions1. prediction would include where, when, and 1. prediction would include where, when, and

how stronghow strong a. people can be moved from areas in dangera. people can be moved from areas in danger b. could plan better growth of citiesb. could plan better growth of cities c. buildings could be reinforced betterc. buildings could be reinforced better2. warning signals/ prediction methods2. warning signals/ prediction methods a. one of earliest used was behavior of animalsa. one of earliest used was behavior of animals

b. detect changes in earth’s crustb. detect changes in earth’s crust 1) instruments places at faults detect changes in 1) instruments places at faults detect changes in

rock rock movement and increases in strainmovement and increases in strain 2) 2) seismic gapsseismic gaps = sections of active faults that have = sections of active faults that have

not not experienced significant earthquakes for long experienced significant earthquakes for long period of period of timetime a) place where fault is locked and unable to movea) place where fault is locked and unable to move b) strain has increased in areab) strain has increased in area c) no major earthquake in c) no major earthquake in last 30 yearslast 30 years

c. detect slight tilting of groundc. detect slight tilting of ground d. detect strain and cracks in rocks caused by d. detect strain and cracks in rocks caused by

stressstress 1) how much strain accumulated in particular 1) how much strain accumulated in particular

part of part of faultfault 2) how much strain was released during last 2) how much strain was released during last

quake quake along that section of faultalong that section of fault

e. detect small changes in e. detect small changes in earth’s magnetic fieldearth’s magnetic field

f. detect increased natural gas seepage from f. detect increased natural gas seepage from strained or strained or fractured rockfractured rock

g. decrease in speed of local P waveg. decrease in speed of local P wave- longer the decrease, the stronger the - longer the decrease, the stronger the

earthquakeearthquake h. water level in wells often goes up or downh. water level in wells often goes up or down3. controlling force - water injected along a fault 3. controlling force - water injected along a fault

reduced friction and earthquakes were less severe reduced friction and earthquakes were less severe (just being tested)(just being tested)