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UWEC / Communications / COMM 201 / Who killed captain james cook?

Who killed captain james cook?

Who killed captain james cook?

Description

School: University of Wisconsin - Eau Claire
Department: Communications
Course: Geol Natl Parks
Professor: `lori snyder
Term: Fall 2016
Tags: Geology, Volcano, volcanoes, hawaii, and cascades
Cost: 25
Name: Intro to Geology- Hawaii Volcanoes & Cascades Volcanoes
Description: These notes cover the Hawaiian volcanoes and the mountains of the Cascades Mountain range. Content includes types of volcanoes, how they form, which types of damage that can result, positive effects of volcanic eruption, and how we monitor volcanic activity.
Uploaded: 10/19/2016
8 Pages 123 Views 2 Unlocks
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Hawaii Volcanoes National Park


Who killed captain james cook?



∙ The Hawaii Islands are in the middle of the Pacific Plates. ∙ The islands themselves are a chain; eight of them are large, hundreds  smaller.

∙ These islands are the locations of several national parks.

Human History 

∙ 600-1100 A.D.- humans arrive through at least two different migrations of Polynesians from South Pacific.

∙ 1778- islands visited by Captain James Cook; was killed in 1779 by the  natives.

∙ 1850’s-1900’s- immigration of the Chinese, Japanese, Germans, and  Portuguese

o 1880- U.S. geologist James Dwight Dana came to the island ∙ 1898- Hawaii was annexed to the U.S.

∙ 1959- Hawaii became the 50th state in the U.S.


What does meteorology mean?



We also discuss several other topics like What is the source-filter theory of vowel production?
If you want to learn more check out What is a database and why is it beneficial?

Meteorology 

∙ One side of Hawaii gets 450 inches of rain per year; the other side gets only 10 inches per year. If you want to learn more check out What does laissez faire economics mean in government?

∙ Orographic Effect- “rain shadow”; warm, moist air is forced to rise;  occurs on the leeward side of the mountain, the side where the wind is  going to; the other side is dry. We also discuss several other topics like What are the three laws of behavior genetics?

o The prevailing winds in Hawaii come from the northeast, so the  eastern sides of the islands are much wetter than the western  sides.

Endemic Species 

∙ Over 90% of the species found in Hawaii are found nowhere else in the  world.

o (ex. Nene (goose-like), Pueo (owl-like), Hawaiian Monk Seal) ∙ Invasive species are causing extinction; the National Park Service does  nothing to prevent this.


What does the orographic effect mean?



If you want to learn more check out What do we mean by imperialism?

The Hawaiian Hot Spot

∙ Generates a chain of islands that grow from the ocean floor. ∙ When volcanoes move off of the hot spot, they die off. If you want to learn more check out What is the definition of fermentation?

Classification of Igneous Rocks – Review 

∙ Volcanoes that form over oceanic hot spots are mafic in composition. ∙ Low viscosity lava cools to form dense, dark colored rocks.

The Hawaiian Hot Spot Track 

∙ Hawaiians and later James Dwight Dana recognized that the islands in  the chain showed a distinct age progression from the oldest ones being in the NW to the youngest being in the SE.

∙ Using this data from the hot spot track, scientists can determine the  velocity of plate motion.

∙ The Pacific Plate, for example, is moving northwest.

Study of Hot Spot Tracks 

∙ Yields information about mantle dynamics and the motion of tectonic  plates.

∙ The Hawaiian volcanoes are huge.

o The largest is 32,000 feet tall (thought about 14,000 feet is  below sea level). For reference, Mount Everest is 29,000 feet tall.

Hazards Identified by the National Park Service 

∙ Volcanism (including gas releases)

∙ Mass Wasting (slumps and slides)

∙ Coastal Erosion  

∙ Seismicity and Tsunamis

Mafic Volcanism 

∙ Shield volcanoes are composed of many lava flows and have gentle  slopes. (ex. Mauna Loa)

∙ The island of Hawaii consists of five overlapping shield volcanoes. ∙ Hawaii Volcanoes National Park contains two active volcanoes- Mauna  Loa and Kilauea

∙ The lava is low viscosity, so the explosions are non-violent.

Types of Lava Flows 

∙ Pahoehoe- thin and ropey; crumples up; very hot and gassy ∙ A’a- cooler, less gassy; thicker and slower; makes “broken glass” sound

Types of Lava 

∙ Vesicular Basalt- escaping gases from the fluid lavas leave air pockets  called vesicles.

∙ Pillow Basalt- underwater eruption (and flow into surface water) Landforms of Mafic Lava Flows 

∙ Lava tubes

∙ “Sky lights”

∙ Calderas- features formed by the collapse of overlying rock into an  evacuated magma chamber

∙ Fumaroles- vents where volcanic gasses escape- amount and type of  gasses can be used to monitor volcanoes

∙ VOG- SO2 + sunlight + H2O + dust = H2SO4 + aerosols = volcanic  smog

Rift Zones 

∙ Rift- extensional fissure in the Earth’s crust; forms from divergent plate boundaries; essentially, the volcano is cracking.

∙ Fissure eruption- often occurs along the rift zone

o Often cause cracks in the road, a hazard.

o As volcanoes fall apart, gases escape.

Hawaiian Hazards 

∙ The islands are gravitationally unstable and are in danger of collapsing  into the ocean- large landslides on the ocean floor have been  documented.

∙ Lahars (mudslides) are not a consequence of volcanic eruptions. Hawaiian Cinder Cone Fields 

 ∙    Cinder cones- small, steep sided volcanoes built of mafic ash, scoria,  and lava

Life Cycle of a Hawaiian Island 

∙ Volcanoes sit on the ocean floor, about 18,000 feet deep. As they move off of the hotspots, they cool and subside, often becoming seamounts.  ∙ Loihi is a new island which is currently forming, and will be complete in  a couple thousand years more.

VOLCANOES OF CASCADE RANGE

∙ The Cascade Range is a continental volcanic arc- a chain of  stratovolcanoes formed on the edge of a continent.

∙ These volcanoes are active.

∙ Convergent Boundary: in this case, oceanic-continental.  ∙ Intermediate composition.

Shield Volcanoes vs. Stratovolcanoes 

∙ Stratovolcanoes are smaller than shield volcanoes in volume and  elevation.

∙ Stratovolcanoes erupt more often than shield volcanoes. ∙ Stratovolcanoes have steeper slopes.

∙ Stratovolcanoes have more violent eruptions than shield volcanoes.

Mt. St. Helens Volcanic Research Center 

∙ Created in 1982 after the 1980 eruption; managed by USFS. ∙ Home of the Confederate Tries of Umatilla Indian Reservation; Treaty  with U.S. Government in 1855.

∙ Area covers NE Oregon and SE Washington.

∙ Mt. St. Helens is still an active volcano.  

Composite Volcanoes/ Stratovolcanoes 

∙ Composed of lava flows and pyroclastic materials; have relatively steep slopes.

∙ Intermediate composition.

∙ A depression often forms on top called a crater, a feature formed from  an explosion.

Volcanic Activity 

∙ Stratovolcanoes often produce large volumes of ash that impact other  Earth systems and the Biosphere.

o Ash good for soil.

o Ash in the atmosphere causes global cooling. (ex. Mt. Pinatubo  1991)

Pyroclastic Rocks 

∙ Pumice- frothed volcanic class; will float on water

∙ Tuf- volcanic fragments commonly welded together

Mt. St Helens Eruption 1980 

∙ First time that the U.S. Geological Survey was able to see the entire  eruptive sequence.

∙ May 18th, 1980 at 8:32 A.M.  

∙ Hundreds of millions of dollars in damage.

∙ 57 deaths, most not directly caused by eruption.

∙ Several things happened as a result of the eruption.

Volcanic Processes/Deposits: Blast 

∙ Trees were knocked down by a lateral blast from the north side.

Volcanic Processes/ Deposits: Landslide 

∙ As a result of a landslide, giant rocks fell into the lake and the river  valley, causing the water to not be able to move.

Pyroclastic Flow 

∙ Pyroclastic flow was caused by the volcano’s dome collapsing and  expanding gasses. (very hot, gassy, ashes)

∙ Can reach velocities of 300-400 km/hr, temps as high as 500-700  degrees Celsius

∙ Coated area with pumice, tephra, and ash.

Ash Columns and Ash Fall 

∙ Volcanic ash clogs combustion engines, aggravates respiratory  ailments, and buries homes and agricultural lands.  

∙ Ash columns may reach altitudes of 25 miles or higher; allows volcanic  ash to travel around the world by wind.  

∙ High in vitamins K and P, which develops rich soils.

Volcanic Processes/ Deposits: Tephra 

∙ Tephra- clastic material ejected from a volcano; pieces of rock and ash

Lahars 

∙ Lahars- form when volcanic ash mixes with water; creates mudflows,  which can occur without warning long after an eruption, very  destructive

∙ Plug up river channels, cause flooding

∙ Most people killed in the Mt. St. Helens eruption were killed by lahars

Lava Domes 

∙ May form prior to or after an eruption- a collapse often triggers  pyroclastic flows

∙ Grows then destroys itself over time; repeats itself

Mt. St Helens Sediment Dam 

∙ Constructed to capture lahars

∙ Landslide blocks fish migration

CRATER LAKE

∙ Mt. Mazama was a volcano until it erupted 6,700 years ago, leaving  behind a hole in the ground, which would become Crater Lake.  ∙ Crater Lake is North America’s deepest lake.

∙ Found in Oregon.

∙ The Makalaks believed that the lake was so holy that looking at it could cause death.

∙ No rivers, so no fish, very clear. The Europeans added fish and food  sources for the fish, so it is less clear than it was in the past. ∙ To say that the lake was formed by a crater is wrong; it is actually a  caldera that formed after rock collapsed into an empty magma  chamber, a.k.a. a caldera.  

∙ Wizard Island, formed from lava flow into the lake, is a cinder cone.  ∙ Deposits of ashfall near Crater Lake are up to 60 feet thick.

The Crater’s Lake 

∙ 4.6 trillion gallons of water from rain and snow melt.

∙ 1,932 feet deep.  

∙ More than 500 inches of snow fall per year on average.  

MT. RAINIER, WA

∙ 4,393 meters tall (14,410 feet); highest peak in the Cascades Range. ∙ Close to population centers.

∙ Active volcano.

∙ Capped by snow and glaciers, increasing the likelihood of lahars.  ∙ The most dangerous volcano in the Cascades.  

Mt. Rainier National Park, WA 

∙ Established March 2nd, 1899.

∙ 2 million visitors annually.  

∙ Mt. Rainier has the largest single-peak glacier system in the contiguous states.  

∙ Lahar damage is high around Mt. Rainier.  

o 6,700 years ago, a lahar buried the Seattle/ Tacoma area.  

What Do We Do?  

∙ We monitor volcanoes and alert the population of dangers.  ∙ Monitoring seismic activity, gasses, and deformations can help. ∙ Lahar detection (only done for stratovolcanoes) consists of pointing  

lasers at major river valleys. If there is excess water, a siren will go of,  alerting others to go to higher ground.  

∙ Cannot be done for shield volcanoes.

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