Earthquakes
Advertisement
This presentation is the property of its rightful owner.
1 / 36

Earthquakes PowerPoint PPT Presentation

1959 earthquake at Hebgen Lake, MT. 1995 landslide in La Conchita, CA. EARTHQUAKES ... PRINCIPAL EARTHQUAKE ZONES. Intraplate Earthquakes ...

Download Presentation

Earthquakes

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Earthquakes

POSER?

If you place an ice cube in a glass of water and mark the water level, when the ice has fully melted, will the water level by higher, lower or the same?


Earthquakes

EARTHQUAKES

EFFECTS OF EARTHQUAKES

LANDSLIDES AND LIQUEFACTION

Shaking and tremors dislodge unstable masses of rocks

and soil on hillsides.

Fragments can be dislodged from bedrock and

buildings as well.


Earthquakes

EARTHQUAKES

EFFECTS OF EARTHQUAKES

LANDSLIDES

1959 earthquake at Hebgen Lake, MT

1995 landslide in La Conchita, CA


Earthquakes

EARTHQUAKES

EFFECTS OF EARTHQUAKES

FALLING DEBRIS


Earthquakes

EARTHQUAKES

EFFECTS OF EARTHQUAKES

LIQUEFACTION

Conversion of unconsolidated material with some

initial cohesiveness in to a mass of water-saturated

sediment that flows like a liquid, although no

water has been added.

Shaking increases the pressure on the water between

the sediment grains, forcing them apart

Loss of frictional contact produces a slurry of sediment

and mud


Earthquakes

EARTHQUAKES

EFFECTS OF EARTHQUAKES

LIQUEFACTION

Turnagain Heights, AK

1964

Government Hill Elementary School

Anchorage, AK, 1964


Earthquakes

EARTHQUAKES

EFFECTS OF EARTHQUAKES

LIQUEFACTION

Kobe, Japan


Earthquakes

EARTHQUAKES

EFFECTS OF EARTHQUAKES

LIQUEFACTION

Kobe, Japan


Earthquakes

EARTHQUAKES

EFFECTS OF EARTHQUAKES

LIQUEFACTION

Port Royal, Jamaica

1692

City slid 15 m below

sea level.


Earthquakes

EARTHQUAKES

EFFECTS OF EARTHQUAKES

SEICHES (pronounced sayshes)

Seismic waves cause water

in an enclosed basin

to oscillate.

Can occur miles from the

focus or epicenter of

the earthquake.


Earthquakes

EARTHQUAKES

EFFECTS OF EARTHQUAKES

TSUNAMI

Translated from Japanese means “harbor wave”.

Not a “tidal wave”.

TSUNAMI is a very long wavelength, high-speed

ocean wave, produced by earthquakes.

Wavelength can be up to 160 km.

Velocities reach 800 km/hr (500 mph).

Generally imperceptible at sea, crest only 1 m high.

Water bunches up when the wave “feels bottom”.

Wave height can reach 65 m (210’).


Earthquakes

EARTHQUAKES

EFFECTS OF EARTHQUAKES

TSUNAMI

Produced by large, rapid displacement of sea floor

due to submarine faulting.

Can also be produced by submarine landslides.

Tsunami hitting Hawaii following an

earthquake in Alaska in 1946


Earthquakes

EARTHQUAKES

EFFECTS OF EARTHQUAKES

TSUNAMI

1964 Anchorage Earthquake


Earthquakes

EARTHQUAKES

EFFECTS OF EARTHQUAKES

FIRE

Fire is not directly a result of earthquakes, but fire

certainly accompanies earthquakes in

industrialized setting.

Earthquakes rupture gas mains, oil tanks and power

lines.

They also break water mains which makes fire fighting

difficult.


Earthquakes

EARTHQUAKES

EFFECTS OF EARTHQUAKES

FIRE

1906 San Francisco Earthquake


Earthquakes

EARTHQUAKES

EFFECTS OF EARTHQUAKES

Anchorage, AK

FIRE

Kobe, Japan


Earthquakes

EARTHQUAKES

PRINCIPAL EARTHQUAKE ZONES


Earthquakes

EARTHQUAKES

PRINCIPAL EARTHQUAKE ZONES

Most earthquakes happen at plate boundaries.

Divergent Boundaries

Have shallow focus and low magnitude.


Earthquakes

EARTHQUAKES

PRINCIPAL EARTHQUAKE ZONES

Transform Boundaries

Have shallow focus and high magnitude.


Earthquakes

EARTHQUAKES

PRINCIPAL EARTHQUAKE ZONES

Convergent Boundaries

Have deep focus and high magnitude.

Deeper focus due to subduction (depths up to 700 km).


Earthquakes

EARTHQUAKES

PRINCIPAL EARTHQUAKE ZONES

Benioff-Wadati Zone


Earthquakes

EARTHQUAKES

PRINCIPAL EARTHQUAKE ZONES

Benioff-Wadati Zone


Earthquakes

EARTHQUAKES

PRINCIPAL EARTHQUAKE ZONES

Benioff-Wadati Zone


Earthquakes

EARTHQUAKES

PRINCIPAL EARTHQUAKE ZONES

Intraplate Earthquakes

Generally have shallow focus and low magnitude.

Lower strain due to location away from plate margins.

However…...

Intraplate rocks are older and colder and more brittle.

Less fractured at mid-continent.

Thus they transmit seismic waves more efficiently.


Earthquakes

EARTHQUAKES

Date-Time 2002 04 20 6:50:44.7

Location: 44.507N 73.664W

Depth: 5 kilometers

Magnitude: 5.1

Region: near Ausable Forks, NY


Earthquakes

EARTHQUAKES

PRINCIPAL EARTHQUAKE ZONES

Intraplate Earthquakes

New Madrid, MO

Largest recorded earthquake

in North America.

Occurred in 1811, lasted

53 DAYS!

Three main quakes had

magnitudes of ~8.5!

1500 aftershocks.

Moved position of Mississippi

River

Rang church bells in

BOSTON!


Earthquakes

EARTHQUAKES

PRINCIPAL EARTHQUAKE ZONES

Intraplate Earthquakes

New Madrid, MO


Earthquakes

EARTHQUAKES

PRINCIPAL EARTHQUAKE ZONES

Intraplate Earthquakes

New Madrid, MO


Earthquakes

EARTHQUAKES

PRINCIPAL EARTHQUAKE ZONES

Intraplate Earthquakes

New Madrid, MO (1811) vs. San Francisco, CA (1906)


Earthquakes

EARTHQUAKES

OTHER EARTHQUAKE FEATURES

SEISMIC GAP

Parts of faults “stick”.

Friction prevents movement in that part of the fault.

Force is applies, rocks are stressed.

When friction is overcome, fault movement occurs.

Areas where major earthquakes could occur.


Earthquakes

EARTHQUAKES

SEISMIC GAP


  • Login