volcano
seismic activity
a vent in the earth's crust through which lava, steam,
ashes, etc., are expelled
seismic - of or relating to earthquakes or other
vibrations of the earth and its crust
earthquake
tremors
earth tremor - a small earthquake; shaking and
a sudden and violent shaking of the ground, sometimes vibration at the surface of the earth resulting from
causing great destruction, as a result of movements
underground movement along a fault plane or from
within the earth's crust or volcanic action
volcanic activity
aftershock - tremors occurring after the main shock of
an earthquake
foreshock - a tremor preceding an earthquake
glacier
sediment
Glaciers are made up of fallen snow that, over many
years, compress into large, thickened ice masses.
Glaciers form when snow remains in one location long
enough to transform into ice. What makes glaciers
unique is their ability to move. Due to sheer mass,
glaciers flow like very slow rivers. Some glaciers are
as small as football fields, while others grow to be
dozens or even hundreds of kilometers long.
Sediment is solid material that is moved and deposited
in a new location. Sediment can consist of rocks and
minerals, as well as the remains of plants and animals.
It can be as small as a grain of sand or as large as a
boulder.
eruption
pyroclastic flow
The most common type of volcanic eruption occurs
when magma (the term for lava when it is below the
Earth's surface) is released from a volcanic vent.
Eruptions can be effusive, where lava flows like a
thick, sticky liquid, or explosive, where fragmented
lava explodes out of a vent. In explosive eruptions, the
fragmented rock may be accompanied by ash and
gases; in effusive eruptions, release of gas is common
but ash is usually not.
Pyroclastic flows are a common and devastating result
of some volcanic eruptions.
They are fast-moving fluidized bodies of hot gas, ash
and rock (collectively known as tephra) which can
travel away from the vent at up to 150 km/h.
The gas is usually at a temperature of 100-800 degrees
Celsius.
The flows normally hug the ground and travel
downhill under gravity, their speed depending upon
the gradient of the slope and the size of the flow.
Sediment moves from one place to another through the
process of erosion. Erosion is the removal and
transportation of rock or soil. Erosion can move
sediment through water, ice, or wind.
flash flood
ash fallout
Flash floods are short-term events, occurring
within 6 hours of the causative event (heavy rain, dam
break, levee failure, rapid, snowmelt and ice jams) and
often within 2 hours of the start of high intensity
rainfall. A flash flood is characterized by a rapid
stream rise with depths of water that can reach well
above the banks of the creek. Flash flood damage and
most fatalities tend to occur in areas immediately
adjacent to a stream. Additionally, heavy
rain falling on steep terrain can weaken soil and cause
mud slides, damaging homes, roads and property.
Flash floods can be produced when slow moving or
multiple thunderstorms occur over the same area.
When storms move faster, flash flooding is less likely
since the rain is distributed over a broader area.
Volcanic ash consists of tiny jagged pieces of rock
and glass. Ash is hard, abrasive, mildly corrosive,
conducts electricity when wet, and does not dissolve
in water. Ash is spread over broad areas by wind.
electrostatic field
magnetism in ash
An electric field or electrostatic field describes the
charged area near any electrically-charged object.
Some ash can contain the iron oxide
mineral magnetite. If you plan to travel to a beach on
a tropical volcanic island, take along a strong little
magnet and look for magnetite.
hypothermia
Ring of Fire
Hypothermia is a medical emergency that occurs when
your body loses heat faster than it can produce heat,
causing a dangerously low body temperature. Normal
body temperature is around 98.6 F (37 C).
Hypothermia (hi-poe-THUR-me-uh) occurs as your
body temperature passes below 95 F (35 C).
The Ring of Fire is an area where a large number
of earthquakes and volcanic eruptions occur in the
basin of the Pacific Ocean. In a 40,000 km (25,000 mi)
horseshoe shape, it is associated with a nearly
continuous se ries of oceanic trenches, volcanic arcs,
and volcanic belts and/or plate movements. It has 452
volcanoes and is home to over 75% of the world's
active and dormant volcanoes.
When your body temperature drops, your heart,
nervous system and other organs can't work normally.
Left untreated, hypothermia can eventually lead to
complete failure of your heart and respiratory system
and to death.
Hypothermia is most often caused by exposure to cold
weather or immersion in a cold body of water. Primary
treatments for hypothermia are methods to warm the
body back to a normal temperature.
Falling ash can turn daylight into complete darkness.
Accompanied by rain and lightning, the gritty ash can
lead to power outages, prevent communications, and
disorient people.
succession in environment
Succession is the observed changes in an ecological
community over time. These changes are fairly
predictable and orderly. Within an ecological
community, the species composition will change over
time as some species become more prominent while
others may fade out of existence. As the community
develops over time, vegetation grows taller, and the
community becomes more established.
Primary succession is initiated when a new area that
has never previously supported an ecological
community is colonized by plants and animals. This
could be on newly exposed rock surfaces from
landslides or lava flows.
Secondary succession occurs when an area that has
previously had an ecological community is so
disturbed or changed that the original community was
destroyed and a new community moves in. This is
more common than primary succession, and is often
the result of natural disasters such as fires, floods, and
winds, as well as human interference such as logging
and clear-cutting.
Seasonal succession is another type of succession, but
instead of being the result of a disastrous event, it is
caused by cyclical changes in the environment or
interactions between the species in a community.