Earth Science Study Guide

Briefly describe Maurice and Katia Krafft

Maurice and Katia Krafft were French volcanologists who devoted their lives to documenting volcanoes and specifically volcanic eruptions in still photos and film. The Krafft's died on 3 June 1991 when they were hit by a pyroclastic flow at Unzen volcano in Japan. They loved volcanoes and were very passionate about documenting them.

Briefly describe Mt Pelee

Mount Pelée, French Montagne Pelée, active volcanic mountain on the Caribbean island of Martinique. Situated 15 miles northwest of Fort-de-France, it reaches an elevation of 4,583 feet. Pelée consists of layers of volcanic ash and lavas.

Briefly describe Mt Tambora

Mount Tambora, also called Mount Tamboro, Indonesian Gunung Tambora, volcanic mountain on the northern coast of Sumbawa island, Indonesia, that in April 1815 exploded in the largest volcanic eruption in recorded history. It is now 2,851 metres (9,354 feet) high, having lost much of its top in the 1815 eruption. It is a stratovolcano.

Hawaii and Yellowstone were both created by a deep Earth process called a hotspot. (T/F)?

T.

Strike-slip faults are caused by shear forces. (T/F)?

T.

Briefly describe Laki

The Laki eruption in Iceland, which began in June 1783, was followed by many of the typical climate responses to volcanic eruptions: suppressed precipitation and drought, crop failure, and surface cooling. The 1783-1784 Laki flood lava eruption in Iceland emitted ∼122 megatons (Mt) SO2 into the atmosphere and maintained a sulfuric aerosol veil that hung over the Northern Hemisphere for >5 months. ... In these regions, the annual mean surface cooling that followed the Laki eruption was about −1.3°C and lasted for 2-3 years.

Briefly describe Mt Pinatubo

The Pinatubo eruption on 15 June 1991 was the second largest volcanic eruption of the 20th century. Pinatubo is a complex of lava domes located 100 km NW of Manila city, Luzon Island, Philippines. Prior to the eruption, Pinatubo was a little known volcano and it had been dormant for 400 years.

Sticky lava is very thick. (T/F)?

True

Describe several ways scientists are able to measure volcanic activity. How has this 'science' changed? Give several specific examples.

Volcanologists use many different kinds of tools including instruments that detect and record earthquakes (seismometers and seimographs), instruments that measure ground deformation (EDM, Leveling, GPS, tilt), instruments that detect and measure volcanic gases (COSPEC), instruments that determine how much lava is moving underground (VLF, EM-31), video and still cameras, infrared cameras, satellite imagers, webcams. This science has changed as technology has gotten increasingly complex. For example, (

Define and describe a Lahar

is a violent type of mudflow or debris flow composed of a slurry of pyroclastic material, rocky debris and water. The material flows down from a volcano, typically along a river valley.

Besides being created by volcanoes, what do the Galapagos Islands, the Hawaiian Islands, Iceland and Yellowstone have in common? Describe this unique process. Be specific.

Besides being created by volcanoes, the Galapagos Islands, Hawaiian Islands, Iceland and Yellowstone have other things in common. The main thing these landforms have in common is the fact that they were all formed from sliding over a hotspot. A hot spot occurs because of the intense heat of the outer core. This heat radiates through the mantle bringing hot solid rock upward to the hot spot. These areas of rising solid rock are called mantle plumes. Because of lower pressure in the upper region of the mantle the rock begins to melt. This forms magma which rises inch by inch until it reaches the surface forming a volcano. Millions of years ago the North American plate was hundreds of miles east of where it is today. As the plate moved west it slowly moved over the hot spot that is now under Yellowstone. The hot spot has created volcanic features through the western portion of the United States. This is exactly the same process that formed the Hawaiian Islands. The North American plate continues to move, which means that millions of years from now the hot spot will be under South Dakota or Iowa!!

Molten rock beneath the Earth's surface is called lava. (T/F)?

F, Magma

The fastest seismic waves are the surface waves. (T/F)?

F, The P Wave

A cinder cone volcano has a broad, flat come with gently sloping sides. (T/F)?

F, a shield volcano

Iceland was created by convergent oceanic plates. (T/F)?

F, divergent + hot spot and mid-atlantic ridge.

A gentle, freely flowing eruption comes from lava that has much silica and water vapor. (T/F)?

F, iron and magnesium

The Richter scale measures the intensity of an earthquake. (T/F)?

F, measures the amount of seismic energy released by an Earthquake (Magnitude).

Earthquakes and volcanoes are rarely associated with tsunamis. (T/F)?

F, often

Composite volcanoes have gentle sloping sides. (T/F)?

F, shield volcanoes

Krakatoa, Mt. St. Helens and Mt. Fuji and all shield volcanoes. (T/F)?

F, strato volcanoes

Cinder cone volcano eruptions are gentle and long-lasting. (T/F)?

F, violent and don't last long.

When a volcano erupts, the molten material that flows onto the Earth's surface is called magma. (T/F)?

F. Lava

The Pacific ring of fire refers to an enormous area of volcanic activity that outlines one of the Earth's tectonic plates. (T/F)?

F. Many of the tetonic plates.

Places located in the interior of tectonic plates where magma rises directly to the surface are called rifts. (T/F)?

F. Rift Valleys

Earthquake waves are called Richter waves. (T/F)?

F. Seismic Waves

In an earthquake, the point where the first movement of rock occurs and energy is released is the epicenter. (T/F)?

False,

The Hawaiian islands are amongst the youngest land masses on the Earth. (T/F)?

T

Tsunamis are only a few feet high in shallow water. (T/F)?

T

When two plates move apart, a rift forms. (T/F)?

T

Define and describe Pyroclastic flows and pyroclastic clouds. What causes them? What kind of lava forms these unique events?

A pyroclastic flow (also known as a pyroclastic density current or a pyroclastic cloud) is a fast-moving current of hot gas and volcanic matter (collectively known as tephra) that moves away from a volcano about 100 km/h (62 mph) on average but is capable of reaching speeds up to 700 km/h (430 mph). Pyroclastic flows have their origin in explosive volcanic eruptions, when a violent expansion of gas shreds escaping magma into small particles, creating what are known as pyroclastic fragments. Sticky, thick lava forms these events.

Briefly describe Surtsey

A volcanic island located in the Vestmannaeyjar archipelago off the southern coast of Iceland. ... It was formed in a volcanic eruption which began 130 metres (430 feet) below sea level, and reached the surface on 14 November 1963.

Briefly describe Santorini / Atlantis

Atlantis was described as a circular island, possibly larger than Libya and Asia. It also had a concentric circle pattern with a canal leading from the inland to the sea. The island of Santorini is a crescent-shaped island in Aegean Sea. It has been the site of a lot of volcanic activity over thousands of years

Briefly describe Campi Flegrei

Campi Flegrei means "burning fields" in Italian. The volcanic region is also known as the Phlegraean Fields. Like other supervolcanoes—such as the one responsible for the geothermal features of Yellowstone—it is not a single volcanic cone. Rather, it's a large complex, much of it underground or under the Mediterranean Sea, that includes 24 craters, as well as various geysers and vents that can release hot gas.

Describe Plate Tectonics / Continental drift. Be as specific (detailed) as possible. What evidence is available to scientists to help us understand these processes? Compare and contrast two (2) types of plate interactions (where the plates come together).

Continental drift describes one of the earliest ways geologists thought continents moved over time. Today, the theory of continental drift has been replaced by the science of plate tectonics. The theory of continental drift is most associated with the scientist Alfred Wegener. In the early 20th century, Wegener published a paper explaining his theory that the continental landmasses were "drifting" across the Earth, sometimes plowing through oceans and into each other. He called this movement continental drift, which was a theory scientists did not accept. One of the elements lacking in the theory was the mechanism for how it works—why did the continents drift and what patterns did they follow? Wegener suggested that perhaps the rotation of the Earth caused the continents to shift towards and apart from each other. (It doesn't.) Today, we know that the continents rest on massive slabs of rock called tectonic plates. The plates are always moving and interacting in a process called plate tectonics. Convergent boundaries: where two plates are colliding. Subduction zones occur when one or both of the tectonic plates are composed of oceanic crust. Divergent boundaries - where two plates are moving apart. Divergent boundaries within continents initially produce rifts, which eventually become rift valleys.

A major problem in predicting earthquakes is that no single change in Earth occurs for all earthquakes. (T/F)?

T

Describe the violent and dramatic history of Krakatoa. Give specific details, make comparisons to other related volcanic events. Discuss the destruction and the "new" island. What effect did these past eruptions possibly have on life on Earth, including human beings?

In August 1883, the eruption of the main island of Krakatoa (or Krakatau) killed more than 36,000 people (mostly by tsunami waves), making it one of the most devastating volcanic eruptions in human history. In many aspects, the first global catastrophe. And thanks to modern communications, Krakatau was the first news story to go (literally) around the world. Within two weeks the ash, gases and aerosols were blown by atmospheric winds westwards along the equator. Months after the eruption the volcanic cloud spread from the equatorial to the mid-latitude zones. The fine grains, trapped in the higher layers of earth's atmosphere, scattered the sunlight for many years to come, causing strange optical phenomena, like blood-red skies. Krakatoa lies along the convergence of the Indian-Australian and Eurasian tectonic plates, a zone of high volcanic and seismic activity. Sometime within the past million years, the volcano built a cone-shaped mountain composed of flows of volcanic rock alternating with layers of cinder and ash. From its base, 1,000 feet below sea level, the cone projected about 6,000 feet above the sea. Later (possibly in AD 416), the mountain's top was destroyed, forming a caldera 4 miles across. In 1930, in the caldera formed by the explosion and collapse of the old volcano a new one, Anak Krakatoa, the child of Krakatau, started to grow. The child has grown fast, displaying a continuous activity since its first eruption it rises by 16 feet per year and most probably will keep growing.

At divergent plate boundaries, plates move apart. (T/F)?

T

Briefly describe Sakurajima

Sakurajima is one of the most active volcanoes in the world and can erupt more than a thousand times a year, spewing ash kilometers above the volcano. Sakurajima is a stratovolcano, one of the 16 Decade Volcanoes, and a former island in Kagoshima Prefecture in Kyushu, Japan.

Massive avalanches of hot, glowing rock flowing on a cushion of hot gases are pyroclastic flows. (T/F)?

T

A denser plate slides under a less dense plate and plate material is melted at a divergent plate boundary. (T/F)?

T

Iceland is a volcanologists dream, mainly because there are two(2) massive volcanic and tectonic forces in play. Describe these two forces and the resulting topography (structure) of the island.

The two forces in play, making Iceland a volcanologists dream, are the mid-atlantic ridge and a hot spot. Located on top of a massive plume, Iceland is a known volcanic hotspot and currently has 35 active volcanoes within its borders (BBC, 2010), most of which are along the ridge. Iceland today is extremely active with volcanism and earthquakes. Three rift zones have appeared across Iceland in recent times. This is largely due to the spreading of the mid Atlantic ridge. The Eurasian and North American plates are still in the process of diverging and Iceland is moving with them. The portion of the crust located between two of the rift zones, called Hreppar in South Iceland, is departing with the North American plate. This will allow parts of Iceland that are active to eventually become inactive as it slides away from the hotspot.

Briefly describe Mt Unzen

an active volcanic group of several overlapping stratovolcanoes, near the city of Shimabara, Nagasaki on the island of Kyushu, Japan's southernmost main island. In 1792, collapse of the Mayu-yama lava dome created an avalanche and tsunami that killed an estimated 14,524 people. Most of the people were killed by the tsunami. During 1991-1994, approximately ten thousand pyroclastic flows were counted on Unzen. Landslides also generated large pyroclastic flows that traveled as far as 3.4 miles (5.5 km) from the dome. On June 3, 1991, one of these pyroclastic flows killed 43 people, including noted volcanologists Maurice and Katia Krafft and Harry Glicken.

Briefly describe Heimaey Island

literally Home Island, is an Icelandic island. ... Heimaey is 4 nautical miles (7.4 km; 4.6 mi) off the south coast of Iceland. It is the only populated island of the Vestmannaeyjar islands, with a population of 4,500. Heimaey is the most complex of the islands. Its earliest eruptions occurred in its northernmost part where a cluster of tuff cones was built during subglacial activity. Until mid-January 1973, Heimaey was considered volcanically inactive both by volcanologists and its residents. Thus, the eruption came as a complete surprise. On January 23, 1973, a fissure ripped the island of Heimaey open, releasing a fountain of lava. Lava and ash and debris rained down on the town and surrounding countryside, destroying nearly 400 buildings and forcing everyone to flee for months.