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
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