EARTHQUAKES AND VOLCANOESSECTION 2Monday, May 14Tuesday, May 15

Agenda

Lecture: Earthquakes and Volcanoes Prioritize unit activities Pick 2 options for today (besides lecture)

Other announcements

Schedule for today:8:10-9:05 Assembly9:10-10:25 Period 210:30-11:05 1st lunch11:10-12:35 Period 412:40- 2:00 Period 6

Notes: Earthquakes

What is an earthquake? Earthquakes occur at plate boundaries Earthquakes are vibrations resulting

from rocks sliding past each other at a fault

(Seismic waves are waves of energy released during in earthquake)

Vocabulary Focus the area along a fault at which the

first motion of an earthquake occurs

Epicenter the point on Earth’s surface directly above an earthquake’s focus

Other websites on EarthquakesTypes of faultshttp://www.iris.edu/gifs/animations/faults.htmRecent map of earthquakes

http://earthquake.usgs.gov/eqcenter/recenteqsus/

PNW earthquake websitehttp://www.ess.washington.edu/recenteqs/

latest.htmBasic Earthquake powerpoint

http://earthquake.usgs.gov/learning/eq101/EQ101.htm

PACIFIC NORTHWEST EARTHQUAKE - Magnitude 6.8 February 28, 2001

At 10:54 a.m. on February 28, 2001, a magnitude 6.8 earthquake shook the Pacific Northwest.

Fifteen minutes after the earthquake, Shannon & Wilson dispatched a team of geotechnical earthquake engineers and geologists to investigate the geotechnical aspects of the event.

The team initially focused on sites that had shown historical evidence of ground failure during 1949 (magnitude 7.1) and 1965 (magnitude 6.5) events.

Most of the damage observed was located in Olympia and Tumwater and in artificial fill areas in and around Seattle.

No liquefaction evidence was found in Puyallup where significant liquefaction had occurred in previous earthquake events.

Pictures from Shannon and Wilson Website: http://www.shannonwilson.com/

S06 Lateral Spreading of Road at Sunset Lake Tumwater

A01 Failure of MSE Wall Overview Tumwater

A02 MSE Wall Failure Tumwater

M01 Ground Settlement at Marathon Park Olympia

OB01 liquefaction separated column from foundation by 8 in

U01 Sidewall Failure S of Sodo Center Along First Ave S

Magnitude 7.9 Earthquake - Denali Fault, Alaska - November 3, 2002 Quake_2002

Shortly after the M7.9 earthquake near Denali National Park, Alaska, Shannon & Wilson engineers were on the road to investigate and document geotechnical damage. The team includes Rohn Abbott, Steve Adamczak, Frank Wuttig, Mark Lockwood, and Bill Perkins.

Tree split in 20- to 30-foot wide rupture zone at Milepost 215.7, Richardson Highway.

Same location as photo 11. Note vehicles for scale.

Ground displacement into lake. Note submerged sand boil and vegetation.

Milepost 77.5, approx. 6 ft vertical, 4 ft horiz. movement across road due to liquefaction of soil below road embankment. Displacements typical of much of road embankments between mileposts 78-75.2

Milepost 78, looking north towards Mentasta Lodge east (right) side of road. Approx. 4 ft vertical, 6 ft horiz. displacement across road SW end of landslide-lateral spread into lake on west side of road

Up to 8ft diameter rocks across Red Rock Canyon Road (1.4 miles east of Richardson Highway at milepost 213.6. Note pickup for scale.

Airport-Typical cracking and lateral displacement in runway surface

Airport-Sand boils at lodge. Differ. settle., lat. movement, foundations tilted inter. floors, opened horiz. cracks between floors-walls. Lodge employee saw 4ft high geysers from boil vents

Airport-Typical sand boil in runway

Airport-Settlement of Hanger relative to floor slab has shortened the height of the door opening and prevents door from closing completely. Residents reported that door closed completely prior to earthquake

Airport-Power pole at lodge that sank approx. 3 feet during. Lodge employee present at time of earthquake reported watching pole sink. Note slack guy wires, which were reportedly taught prior to the earthquake

Earthquakes generate three types of waves:

1. Longitudinal waves travel by compressing and stretching crust, also

called primary waves (P waves)

2. Transverse waves travel in an up and downward movement,

also called secondary waves (S waves)(Both P waves and S waves spread out from the focus in all

directions through the earth.)

3. Surface waves (Surface waves move only on Earth’s surface.)

seismic waves that can move only through solids, move in a rolling circular motion

surface waves D:\Ch21\80078.html

Measuring Earthquakes

Seismologists detect and measure earthquakes.

Seismology the study of earthquakes including their origin, propagation, energy, and prediction• Seismologists use sensitive equipment called

seismographs to record data about earthquakes.

• Seismograph D:\Ch21\80079.html

How to calculate the epicenter of an earthquake?

• Because P waves travel faster, the difference between the arrival of P waves and the arrival of S waves allows scientists to calculate how far away the focus is.

• Three seismograph stations are necessary to locate the epicenter of an earthquake.

How to calculate the magnitude of an earthquake? Richter scale a scale that expresses

the magnitude of an earthquake

Magnitude of earthquake D:\Ch21\80105.html

Why does the Pacific Northwest have earthquakes? We are located at a convergent

continental boundary, where two tectonic plates are colliding.

This boundary is called the Cascadia Subduction Zone. It lies offshore and runs from British Columbia to northern California.

The two plates are converging at a rate of about M 3-4 cm/year (1-2 inches/year), and the northeast-moving Juan de Fuca Plate is pushing into North America, causing stress to accumulate.

Earthquakes are caused by the abrupt release of this slowly accumulated stress.

Other websites

Hazards in the PNW/diagram of faults and volcanoes

http://www.pnsn.org/CascadiaEQs.pdf

Volcanoes

What is a volcano?A volcano is any opening in Earth’s crust

through which magma has reached Earth’s surface.

Vent an opening at the surface of Earth through which volcanic material passes.

So we call it magma or lava?Magma that reaches Earth’s surface is called

lava

Magma D:\Ch21\80112.html

Types of Volcanoes

Shield volcanoes

have mild eruptions.

forms a gently sloping mountain.

Shield volcanoes are some of the largest volcanoes.

3 types of volcanoes D:\Ch21\80116.html

Composite volcanoes

Composite volcanoes are made up of alternating layers of ash, cinders, and lava.

The lave is thicker than that of shield volcanoes.

Gases are trapped in the magma, causing eruptions that alternate between flows and explosive activity that produces cinders and ash.

Composite volcanoes are typically tall with steep sides.

Cinder cones• are the most abundant volcano.

•Cinder cones are the smallest and most common volcanoes.

•Large amounts of gas are trapped in the magma, and violent eruptions of hot ash and lava occur.

•Cinder cones tend to be active for only a short time and then become dormant.

Where do volcanoes occur? (there are 3 places)

1) Most volcanoes occur at convergent plate boundaries.

• 75% of the active volcanoes on Earth are located in an area known as the Ring of Fire.

• The Ring of Fire is located along the edges of the Pacific ocean, where oceanic tectonic plates are colliding with continental plates.

Other places to find volcanoes2) Underwater volcanoes occur at

divergent plate boundaries.

• As plates move apart at divergent boundaries, magma rises to fill the gap.

• This magma creates the volcanic mountains that form ocean ridges.

• Iceland is a volcanic island on the Mid-Atlantic ridge that is growing outward in opposite directions.

One more common spot

3) Volcanoes occur at hot spots.• Some volcanoes occur in the middle of plates. Hot spots D:\Ch21\80124.html

Mantle plumes are mushroom shaped trails of hot rock that rise from deep inside the mantle, melt as they rise, and erupt from volcanoes at hot spots at the surface.

• The plumes remain in the same place as the tectonic plate moves, creating a trail of volcanoes.

• The Hawaiian Islands are an example of this type of volcanic activity.

Today’s Work

All students will complete the lecture notes for each section in their handbook/journal.

All students must define any vocabulary from the GLE evaluation sheet that is not familiar to them.

All students will end up with the equivalent of 10 activities (4 sections of notes + 6 activities).

How to pick your activities?

Score of 4 = Lecture notes Score of 3 = Lecture notes + one more

option from section Score of 2 = Lecture notes, review of

content + one more option from list Score of 1 = Lecture notes, review of

content, lab, + one additional activity

Today in Science

On May 14, 1850, the first U.S. patent for this machine was issued to Joel Houghton of Ogden, NY, for an "Improvement in Machines for Washing Table Furniture”

What was this machine that most people now have in their kitchens?

A dishwasher

Today in Science

This female scientist, Williamina Paton Stevens Fleming, was born on 15 May 1857.She was a Scottish-born American astronomer who pioneered in the classification of stellar spectra and the first to discover these types of stars. Prof. Edward Pickering, director of the Harvard Observatory first employed Fleming as a maid, but in 1881 hired her to do clerical work and some mathematical calculations at the Observatory. She further proved capable of doing science. After devising her system of classifying stars by their spectra, she cataloged over 10,000 stars within the next nine years. Her duties were expanded and she was put in charge of dozens of young women hired to do mathematical computations (as now done by computers).  The type of star she discovered will be the fate of our sun one day. What type of star did she discover?

The “white dwarf”

Today in Science

In 1935, at the Franklin Institute, Philadelphia, this scientist was awarded the Benjamin Franklin Medal for his outstanding fundamental contributions to theoretical physics, especially his relativity theory. Who was this famous scientist?

Albert Einstein