Transcript How is an Earthquake measured?

• Where do
earthquakes
and volcanoes
commonly
occur?
– Near plate
boundaries
(edges)
• Why?
– Plate edges
scrape together
causing
vibrations or
where plates
collide (oceanic
and continental
boundaries)
•http://www.yenka.com/freecontent/attachment.action?quick=12o&att=2773
Earthquakes
What: Vibrations caused by the
breaking of rock.
2004 Japan
December 2004, Sumatra
May 2008, China
Oakland, CA. The upper level of the two-level structure roadway has
collapsed onto the lower level. The columns failed in response to the
October 1989 Loma Prieta earthquake. 41 people were killed in the
collapse.
9.0 Earthquake - Japan
March 11, 2011
Damage to Humans
20,896 people killed,
4,647 missing,
5,314 injured,
130,927 displaced
Damage to Infrastructure
Destroyed or damaged:
332,395 buildings,
2,126 roads,
56 bridges
26 railways
How does an earthquake
occur?
• Plates shift position
• Vibrations disrupt the surrounding area
December 1954, Dixie Valley, NV (magnitude 6.8)
The shack was relatively undamaged, despite being
only a few meters from the two- to three-meter offset.
1989 Loma Prieta Fault, CA
7.0 Earthquake Haiti 2010
•http://www.time.com/time/photogallery/0,29307,1953689,00.html
Where do earthquakes occur?
Along fault lines (cracks in the plates) and
plate boundaries
http://baird.si.edu/minsci/tdpmap/viewer.htm
Earthquakes may be deep underground or
right at the surface
(surface quakes cause more damage)
Earthquakes in the last 24 hours
(January 10th)
http://earthquake.usgs.gov/eqcenter/index.php
NJ’s most recent quake
• May 28, 2013
• Magnitude 2.1
• Largest ever in NJ:
– 11/29/1783
– magnitude 5.3
– felt from NH to PA
8/23/11
5.8 earthquake in VA
• Was felt from
GA to ME and
all the way out
to Chicago
http://earthquake.usgs.gov/earthqu
akes/recenteqsww/Quakes/se082
311a.php#summary
How is an Earthquake measured?
• Seismograph measures waves from an
earthquake,
• the ground moves up and down but the
weight with pen stays at the same level.
http://www.youtub
e.com/watch?v=G
bd1FcuLJLQ
Richter Scale
• Lines drawn by the pen determine
magnitude (strength of quake) on Richter
scale
• Scale goes from 0 & up, 6+ causes
serious damage.
• 9.5 highest recorded quake (1960 –
Chile)
Ancient Chinese Seismograph
• 132 AD, Zhang
Heng -scientist
• A central pendulum
swings with a quake,
thus pulling on a
dragon, which releases
a ball into the toad’s
mouth making a sound
and marking the
direction of the quake.
•
http://www.youtube.com/watch?v=GcVFuIccf5c
Damage
• Can crack buildings and roadways (billions
of dollars in damages)
• Can trigger fires, landslides, and tsunamis
• Kills an average of 10,000 people a year.
• 2008 China: over 87,000 people died in a
7.9 magnitude earthquake
Largest and Deadliest
Earthquakes in the World
• Historical Earthquake List:
•
http://earthquake.usgs.gov/regional/world/historical.php
http://earthquake.usgs.gov/eqcenter/eqarchives/year/byyear.php
How to win a Nobel Prize
Unanswered Questions about Earthquakes
 What starts or stops an earthquake?
 Do earthquakes “talk'' to each other? In other
words, does one earthquake trigger the next
earthquake? If so, how/why?
 Can earthquakes be predicted, and if so, how?

http://abcnews.go.com/Technology/DyeHard/elephants-predictearthquakes/story?id=8643318
•
http://abcnews.go.com/Travel/east-coast-earthquake-animals-zoos-reacted-temblorbegan/story?id=14371679
Earthquake Safety
• Knowing what to do before, during, and
after an earthquake can help you and your
family survive.
Build quake resistant buildings that
move with the earth as it vibrates
Earthquake Safety
• Move or secure objects on high shelves
Earthquake Safety
• Stay indoors during the shaking and stand
in a doorway or hide under a sturdy table
away from windows and high objects.
http://www.classzone.com/books/earth_science/terc/c
ontent/visualizations/es1005/es1005page01.cfm?cha
pter_no=visualization
Drop, Cover, and Hold On!
After the quake
• Move outdoors to open areas quickly,
watch for falling objects during aftershocks
Be Aware of Falling Debris
•
Earthquake Safety Tips
BEFORE AN EARTHQUAKE: Have a disaster plan. Choose a safe place in every room. It’s best to get
under a sturdy piece of furniture like a table or a desk where nothing can fall on you. Practice DROP,
COVER AND HOLD ON! Drop under something sturdy, hold on, and protect your eyes by pressing your face
against your arm. If you live in an earthquake prone area, bolt tall furniture to the wall and install strong
latches to cupboards. Prepare a disaster supplies kit for your home and car. Include a first aid kit, canned
food and a can opener, bottled water, battery-operated radio, flashlight, protective clothing and written
instructions on how to turn off electricity, gas, and water.
DURING AN EARTHQUAKE: DROP, COVER AND HOLD ON! Stay indoors until the shaking stops. Stay
away from windows. If you’re in bed, hold on and stay there, protecting your head with a pillow. If you’re
outdoors, find a clear spot away from buildings, trees and power lines. Then, drop to the ground. If you’re in
a car, slow down and drive to a safe place. Stay in the car until the shaking stops.
AFTER THE SHAKING STOPS: Check for injuries. Inspect your home for damage. Eliminate fire hazards,
so turn off the gas if you think its leaking. Expect aftershocks. Each time you feel one, DROP, COVER AND
HOLD ON.
Tsunamis
http://www.youtube.com/watch?v=5-zfCBCq-8I
http://www.youtube.com/watch?v=dJBS94GVyuo
What is a tsunami?
• Japanese words tsu (harbor) and nami (waves)
• It is a wave or series of waves in the ocean that
can be hundreds of miles long and have been
known to reach heights of up to 45 ft
• Waves can travel at speeds close to 300 mph
• They can cause massive damage and kill many
along coastal lands.
How does it happen?
• Triggered by underwater earthquakes
which forces the water upward
• The wave moves outward in all directions
• As a wave reaches shallow water, it slows
down and gets taller.
http://www.youtube.com/watch?v=chbbiSCczB8
http://www.pep.bc.ca/tsunamis/causes_2.htm
http://www.pbs.org/wnet/savageearth/animations/tsunami/main.html
http://www.usatoday.com/news/graphics/tsnumai/flash02.htm
• Prior to this earthquake the
Indian Plate was moving
beneath the Burma Plate,
meeting resistance and
compression forces
accumulated. When the fault
between these two plates
suddenly slipped a rupture
approximately 1,200 kilometers
long developed in the ocean
floor with a vertical
displacement of about 15
meters. The boundary between
the plates and the line of failure
are shown on the map below as
the blue saw-tooth line.
Contour lines-arrival time, colorswave height
Can I surf a Tsunami Wave?
Typical Tsunami Wave
vs. Typical Wind-generated Wave
Wave Feature
Windgenerated
Wave
Tsunami Wave
Wave Speed
5-60 mph
(8-100 kph)
500-600 mph
(800-1,000
kph)
Wave Period
5 to 20 seconds 10 minutes to 2
(time required for two waves to pass a
apart
hours apart
single point in space)
Wave Length
(horizontal distance between two
waves)
300-600 feet
apart
(100-200
meters
apart)
60-300 miles apart
(100-500 km
apart)
No- there is no face to the wave
Surfing wave
Tsunami wave
Dec. 2004 Tsunami
• 9.2 Earthquake in Indian Ocean caused it
• Killed 230,000 people
• Made clear that tsunami warning systems are
needed globally
2011 Tsunami in Japan
http://www.youtube.com/watch?v=5-zfCBCq-8I
http://www.nytimes.com/interactive/2011/03/11/world/asia/maps-of-earthquake-and-tsunami-damage-in-japan.html?ref=asia
1960
9.5
Chile
Saving lives
• Currently there is a
warning system in the
Pacific Ocean. (none in
the Indian or Atlantic
Oceans)
• Buoys alert satellites,
which relay information to
scientists who issue
warnings to countries.
• Evacuation alarms will
sound.
Warning system
If you see the water receding from the
shoreline, move to higher ground
immediately!
Tsunami wave
Review: http://www.youtube.com/watch?v=chbbiSCczB8&feature=related
Tilly Smith warns family: http://abcnews.go.com/2020/video?id=6707152
http://www.howstuffworks.com/tsunami.htm
Could it happen here?
http://www.youtube.co
m/watch?v=9e8CRE3l
RdA
• Family survives 2004 tsunami
http://www.youtube.com/watch?v=6l-fBxtGFrA
• Tsunami ground zero 2004
http://www.youtube.com/watch?v=Hq_PoQDyqwQ
• The Impossible Trailer
http://www.youtube.com/watch?v=Bgw394ZKsis
Earthquake and Tsunami Review
What type of plate boundary
produces earthquakes?
• Convergent, Divergent, and Transform
Where do we see the most
earthquakes occur?
• Near plate boundaries
What should you do to stay safe
during an earthquake?
• Drop, cover, and hold on
• After the quake, evacuate the building and
move to an open area.
What causes a tsunami?
• Underwater earthquakes, usually at
convergent plate boundaries.
How do you stay safe during a
tsunami?
• If an earthquake has occurred and you are
near water, move quickly to higher ground
or far inland.