ELS module 3 Flashcards
beyond human control.
NATURAL HAZARD
due to accidents, carelessness or inability to implement
protective measures.
HAZARDS INDUCED BY HUMANS
because of personal and political interests.
PLANNED BY PEOPLE
is the process of recognizing hazards that
may arise from a system or its environment, documenting
their unwanted consequences and analyzing their
potential causes.
Hazard analysis
the term signifies a vent, hill, or mountain from which molten or hot rocks with gaseous materials are ejected.
volcano
´ Takes place when two plates converge.
Subduction
Takes place when volcanic gases accumulate and
the pressure becomes too great inside the magma
chamber. The volcano then expels lava, rocks, ash
and gas.
Volcanic eruption
– currently erupting or is showing
signs of volcanic eruption. Erupted within
the last 600 years
Active
– is one which has
erupted and then entered a long period
of inactivity
Potentially active
one that has not shown any
sign of activity for a long period. It has no
record of volcanic eruption in the past
thousand years.
Inactive
mass of magma that flows down the slope of the
volcano at a rate of 3 kilometers per day
Lava flow
refers to hot dry masses of fragmented volcanic
materials that move along the slope and in contact with ground
surface at a speed greater than 60 kilometers per hour.
´ Pyroclastic flow
are showers of fine to coarse-grained volcanic
materials and other airborne products of a volcanic eruption.
Tephra falls
– are rocks that are released into the air by an
erupting volcano.
Ballistic projectiles
one of the basic components of magma or lava.
Active and inactive volcanoes may release gases to the
atmosphere in the form of water vapor, hydrogen sulfide, sulfur
dioxide, carbon monoxide, carbon dioxide, hydrogen chloride
and hydrogen fluoride.
Volcanic gas
– flowing mixture of volcanic debris and water. It is classified
into two:
´ Primary of hot lahar
´ Secondary or cold lahar
´ Lahar
- explosion driven by steam
produced by heating and expansion of
groundwater due to an underlying hot
source.
Phreatic
- eruption resulting from
the ejection of magmatic gases and steam
produced by the conversion of groundwater
to steam by ascending magma, mixed with
water, fine ash and variably-sized volcanic
bombs fragmented from the pre-existing
rock formations, and fresh magmatic ejecta
Phreatomagmatic
weak to violent eruption characterized by lava fountaining and
effusion of molten lava. Typical ejecta are ovoid and fusiform bombs and scoria
(cinders). Ash is relatively minor in amount and eruption cloud is generally yellowish
to white in color
Strombolian
eruption resulting from the release of large quantities of
accumulated magmatic gas which lefts fine ashes and blocks coming
from the magma with great force high in the air forming voluminous
eruption clouds.
Vulcanian
eruption caused by the release of large
quantities of gas from an extremely viscous
magma that hurls out ash and other pyroclastic
materials and is characterized by the presence of
nuee ardente or glowing avalanche consisting of
hot gases
Peleean
- eruption of great violence characterized by voluminous explosive
ejections of pumice and pyroclastic flows. The extrusion of gas-rich magma is
commonly accompanied by collapse of the top of the volcanic cone forming a
caldera.
Plinian
