Transcript Volcanoes Explosive-non explosivex

Today’s Goal: Look at examples of volcanic eruptions
Homework: Study for Geology test
Warm-up: Read page 156-157 and record chart on the
board in your notes
Explosive
Non-Explosive
Second most explosive eruption of the 20th century
Click to see the
others on the list.
Philippines, 1991
Take a moment
to re-read p. 161.
In 79 AD, the Roman city of Pompeii
was virtually wiped off the face of
the Earth when nearby Mt. Vesuvius
erupted a colossal ejection of
volcanic debris. The eruption left a
layer of volcanic ash stretching 32
km.
Pompeii
In the second phase of the eruption,
pyroclastic flow engulfed the people
of the city in fast-moving currents of
superheated gas (1,000°C) and rock
that swept down to ground level.
This led to the burning and
asphyxiation of all life that stood in
harm’s way.
Over 1,000 casts have been made of the
bodies that were engulfed by the pyroclastic
flow. Their impressions were essentially
“frozen” in time exactly as they were at the
time of the eruption.
Mt. Vesuvius (present day)
The volcano has erupted over 30 times since then.
The last time was in 1944.
• Shield volcano
 Broad, slightly domed
 Primarily made of basaltic lava flow – Low viscosity  non-explosive
 Can grow to be huge in size
 e.g. Mauna Loa in Hawaii
• Cinder cone
 Built from ejected lava fragments (pyroclastic material)  explosive
 Steep slope angle
 Rather small in size
 Frequently occur in groups
• Composite cone (or stratovolcano)
 Most are adjacent to the Pacific Ocean (e.g. Mt. Rainier, Mt. St. Helens)
 Large size
 Layered lava and pyroclastic debris  both explosive and non-explosive
 Most violent type of activity
Complete: Some Go POP Some Do Not worksheet. One
per person.
Minerals:
• mineral
• crystalline structure
• silicate/non-silicate
• luster
• streak
• cleavage/fracture
• hardness
• density
The Rock Cycle:
• rock
• rock cycle
• weathering
• erosion
The Rock Cycle (cont.):
• deposition
• texture
• composition
• igneous
• sedimentary
• metamorphic
• intrusive/extrusive
• mafic/felsic
• stratification
• cementation
• foliated/non-foliated
Plate Tectonics:
• crust
• mantle
• inner/outer core
• lithosphere
• asthenosphere
• mesosphere
• tectonic plates
• continental drift
• seafloor spreading
• mid-ocean ridge
• magnetic reversal
• subduction
• trench
• convergent
• divergent
• transform
Earthquakes:
• seismograph
• P waves
• S waves
• epicenter
• focus
• magnitude
• Richter/Mercalli
Volcanoes:
•cinder cone
• composite (strato) volcano
• shield volcano
•viscosity
• explosive/non-explosive
• hot spot volcano
Homework:
Study for test on 12/1!