REFERENCE: The Blue Planet An Introduction to Earth System Science. Brian J. Skinner and Barbara W. Murck (2011) Third Edition. John Wiley and Sons Inc.

PLATE BOUNDARIES OCEAN FLOOR

SEISMIC ACTIVITY WORLD'S VOLCANOES

VOLCANO: Is a vent from which magma,

solid rock debris, and gases are erupted.

MAGMA: Is the mixture of molten rock,

suspended minerals grains, and dissolved gases that forms in the crust or mantle when temperatures are sufficiently high.

LAVA: Is the magma that reaches the

Earth's surface.

1. It has a range of compositions, but Silica (SiO2) is always predominant.

2. It has the properties of a liquid (ability to flow).3. It is characterized by high temperatures.

The average compositions of the solid part of the three principal kinds of magma. In addition to the solid materials, the magmas also contain dissolved gases. Basaltic magma has a low content of dissolved gas; andesitic and rhyolitic magmas tend to be very gassy.

Diagram illustrating the locations of the major kinds

of volcanoes in a plate-tectonic setting.

The Ring of Fire around the Pacific Ocean basin is formed by

andesitic volcanoes. The Ring of Fire is coincident with subductionzones where lithosphere capped with oceanic crust is being subducted into the asthenosphere. Volcanoes in the Pacific Ocean, such as Mauna Loa, erupt basaltic magma but not andesitic magma.

Long-lived hot spots (magma sources) deep in the mantle can be used to determine the absolute motions of plates. Because the hot spots lie far below the lithosphere and do not move laterally, each is marked by a chain of volcanoes on the surface of the lithosphere. The youngest volcano in a chain lies directly above the hot spot.

Hawaiian Hot Spot

Bora Bora was formed around four million years

ago after volcanoes erupted from the sea bed. As

the volcano sank back into the Pacific Ocean, a

ring of coral reefs, or atolls, formed to mark the

ancient coastline. The infamous Bora Bora

lagoon also formed between the reef and the

island around this time. The volcanic core that

still remains on the main island of Bora Bora is

actually sinking at a rate of one centimeter per

century. It will take about 25 million years for

Bora Bora’s main island to sink completely into

the ocean, leaving just a coral atoll.http://www.internationalcircuit.com/bora-bora/history.php

Watch the YouTube video called

“How the Earth Was Made: Hawaii”

A lethal cloud of CO2 bubbled up from the bottom of Lake Nyos after the stratification of the lake water was disturbed. The gas, which is invisible and heavier than air, flowed over the natural dam surrounding the lake and down the adjacent valley.

The ash plume of southwestern Iceland's Eyjafjallajokull volcano streams southwards over the Northern Atlantic Ocean in a

satellite photograph made April 17, 2010. The erupting volcano in Iceland sent new tremors on April 19, but the ash plume

which has caused air traffic chaos across Europe has dropped to a height of about 2 km (1.2 mi), the Meteorological Office

said. (REUTERS/NERC Satellite Receiving Station, Dundee University, Scotland)

Mount Merapi, in Java (Indonesia)

Cleveland Volcano

at Aleutian Arc, Alaska

ISS- Digital Camera

This is a satellite image showing

the area around Mount Vesuvius

and the bay of Naples, Italy.

Vesuvius, an active volcano, is the

circular structure, center right.

Recent lava flows show up bright

red in this image, which recorded

infrared radiation (heat). Older

lavas and volcanic ash show up as

yellows and oranges. The dark

blue and purple region at the head

of the bay is the city of Naples.

Left of Naples, near the center of

the image, is a cluster of small

volcanoes called the flegreian

fields. Changes in the temperature

of the ground surface can be

monitored by comparing

successive satellite images,

because infrared imagery is

sensitive to the temperature of

ground materials.

INFRARED IMAGES

GPS

Horizontal displacement of GPS benchmarks

on Mauna Loa and Kilauea volcanoes, Hawaii

Map showing direction and amount of horizontal displacement (blue vectors) of GPS

stations on Mauna Loa and Kilauea volcanoes relative to a permanent GPS station

located on Mauna Kea (north of Mauna Loa) between June 2000 and July 2001.

TOMS Measurements of

Volcanic Emissions

Sulfur Dioxide (SO2) Ash and Aerosols

These false-color images are from the June 16, 1991 eruption of Mt. Pinatubo, Philippines.

The gas and ash clouds were tracked by TOMS for several weeks as they encircled the

Earth. These satellite observations demonstrate the enormous amounts of gas and ash

emitted, as well as details such as differences in peak concentrations and geographic

extent. TOMS also detects many smaller volcanic clouds

http://www.caribbeanvolcanoes.com/

SOUFRIERE HILLS

MONTSERRAT

-Began erupting on July 18, 1995

-Dome collapse on June 25, 1997

-An ash cloud erupted from the

Volcano on October 27, 1999

Advanced Very High Resolution Radiometer

(AVHRR)

Band Wavelength (mm)

1 0.58-0.68

2 0.72-1.10

3 3.55-3.93

4 10.5-11.5

5 11.5-12.5

Watch the YouTube video called

“Volcanoes 101”