Here's some previous answers I saw:Earthquakes in Hawai`I are closely linked to volcanism. They are an
important part of the island-building processes that have shaped the
Island of Hawai`I and the other Hawaiian Islands. Thousands of
earthquakes occur every year beneath the Island of Hawai`I.Eruptions
and magma movement within the presently active volcanoes (Kilauea,
Mauna Loa and Lo`ihi) are usually accompanied by numerous small
earthquakes. They originate in regions of magma storage or along the
paths that magma follows as it rises and moves prior to eruption. These
are loosely termed volcanic earthquakes.Many other earthquakes,
including the largest ones, occur in areas of structural weakness at the
base of Hawai`I's volcanoes or deep within the Earth's crust beneath
the island. These are referred to as tectonic earthquakes. In the past
150 years, several strong tectonic earthquakes (magnitude 6 to 8) caused
extensive damage to roads, buildings, and homes, triggered local
tsunami, and resulted in loss of life. The most destructive
earthquake in Hawai`I's history occurred on April 2, 1868, when 81
people lost their lives. With a magnitude of 7.9 and a maximum intensity
of XII, this destructive earthquake destroyed more than a hundred homes
and generated a 15-m high tsunami along Kilauea's south coast.SeismographAlong
with other signs of volcanic activity, we monitor earthquakes and
seismic activity on Hawai`I continuously and in real-time to provide
warnings of impending eruption and to assess seismic hazards in the
State of Hawai`I.ETHAL LAKE--Lake Nyos, Cameroon
Threat: Volcanic Activity
Lake Nyos Lake Nyos is a crater lake in the
Northwest Province of Cameroon. Nyos is a deep lake high on the flank of
an inactive volcano in the Oku volcanic plain along the Cameroon line
of volcanic activity. A natural dam of volcanic rock hems in the lake
waters. looks deceivingly peaceful. No one expected that on an
August night in 1986, a million tons of carbon dioxide (C[O.sub.2])
would suddenly burst out of its waters. The huge cloud of gas pushed out
all the oxygen-rich air from the surrounding villages, suffocating suf·fo·cate v.
Suf·fo·cat·ed, suf·fo·cat·ing, suf·fo·catesv.tr.1.
To kill or destroy by preventing access of air or oxygen.2.
To impair the respiration of; asphyxiate.3. 1,700
people
and thousands of animals in their sleep. Those who survived were
quickly evacuated from the region.
What caused the deadly blast? Lake Nyos sits in a crater of an
inactive volcano. The source of all the carbon dioxide was a pool of
cooling magma, or molten rock, 80 kilometers (50 miles) below the lake.
Normally, harmless amounts of C[O.sub.2] are gradually
released
from volcanic lakes when seasonal changes cause cold and warm layers of
water to mix. Cameroon's tropical
climate A tropical climate is a
type of climate typical in the tropics. Köppen's widely-recognized
scheme of climate classification defines it as a non-arid climate in
which all twelve months have mean temperatures above 18°C (64.4 °F). kept
water temperatures
constant year-round and C[O.sub.2] began to build up in the bottom of
the lake. That is, until a landslide or other event disturbed the lake
and triggered the gas to rush to the surface, says William
Evans William Evans' is the name
of: William Evans (cardiologist), Welsh cardiologist and
publisher William Evans (farmer),Canadian farmer, agronomist,
journalist, and author William Evans (artist), Victorian
portrait painter , a
geochemist with the United
States Geological Survey The United
States Geological Survey (USGS) is a scientific agency of
the United States government. The scientists of the USGS study the
landscape of the United States, its natural resources, and the natural
hazards that threaten it. .
Today, gas is still leaking into the lake from the hot rocks
below,
but scientists are taking steps so Lake Nyos doesn't blow again. A
200 meter (656 foot)-long pipe has been placed in the center of the lake
to de-gas its waters (see diagram, right). The pipe spews a continuous
fountain of carbonated water 40 m (131 ft) into the air.
Degassing degassing(dēgas´ing),adj
related to degasification, the process by which dissolved gas is
removed from water or other liquid solutions. is slowly lowering
the C[O.sub.2] levels, making the lake
safe again. But people from the region have not been allowed to return.
"There is still a danger until all the gas is gone," says
Evans.
Volcanic eruptions are most likely in the Pacific Rim states of
Hawaii, Alaska, Washington, Oregon, and California...MOREhere's a link:www.maar.usvolcanoes.usgs.govnotice that most volcanoes in the northwestern
important part of the island-building processes that have shaped the
Island of Hawai`I and the other Hawaiian Islands. Thousands of
earthquakes occur every year beneath the Island of Hawai`I.Eruptions
and magma movement within the presently active volcanoes (Kilauea,
Mauna Loa and Lo`ihi) are usually accompanied by numerous small
earthquakes. They originate in regions of magma storage or along the
paths that magma follows as it rises and moves prior to eruption. These
are loosely termed volcanic earthquakes.Many other earthquakes,
including the largest ones, occur in areas of structural weakness at the
base of Hawai`I's volcanoes or deep within the Earth's crust beneath
the island. These are referred to as tectonic earthquakes. In the past
150 years, several strong tectonic earthquakes (magnitude 6 to 8) caused
extensive damage to roads, buildings, and homes, triggered local
tsunami, and resulted in loss of life. The most destructive
earthquake in Hawai`I's history occurred on April 2, 1868, when 81
people lost their lives. With a magnitude of 7.9 and a maximum intensity
of XII, this destructive earthquake destroyed more than a hundred homes
and generated a 15-m high tsunami along Kilauea's south coast.SeismographAlong
with other signs of volcanic activity, we monitor earthquakes and
seismic activity on Hawai`I continuously and in real-time to provide
warnings of impending eruption and to assess seismic hazards in the
State of Hawai`I.ETHAL LAKE--Lake Nyos, Cameroon
Threat: Volcanic Activity
Lake Nyos Lake Nyos is a crater lake in the
Northwest Province of Cameroon. Nyos is a deep lake high on the flank of
an inactive volcano in the Oku volcanic plain along the Cameroon line
of volcanic activity. A natural dam of volcanic rock hems in the lake
waters. looks deceivingly peaceful. No one expected that on an
August night in 1986, a million tons of carbon dioxide (C[O.sub.2])
would suddenly burst out of its waters. The huge cloud of gas pushed out
all the oxygen-rich air from the surrounding villages, suffocating suf·fo·cate v.
Suf·fo·cat·ed, suf·fo·cat·ing, suf·fo·catesv.tr.1.
To kill or destroy by preventing access of air or oxygen.2.
To impair the respiration of; asphyxiate.3. 1,700
people
and thousands of animals in their sleep. Those who survived were
quickly evacuated from the region.
What caused the deadly blast? Lake Nyos sits in a crater of an
inactive volcano. The source of all the carbon dioxide was a pool of
cooling magma, or molten rock, 80 kilometers (50 miles) below the lake.
Normally, harmless amounts of C[O.sub.2] are gradually
released
from volcanic lakes when seasonal changes cause cold and warm layers of
water to mix. Cameroon's tropical
climate A tropical climate is a
type of climate typical in the tropics. Köppen's widely-recognized
scheme of climate classification defines it as a non-arid climate in
which all twelve months have mean temperatures above 18°C (64.4 °F). kept
water temperatures
constant year-round and C[O.sub.2] began to build up in the bottom of
the lake. That is, until a landslide or other event disturbed the lake
and triggered the gas to rush to the surface, says William
Evans William Evans' is the name
of: William Evans (cardiologist), Welsh cardiologist and
publisher William Evans (farmer),Canadian farmer, agronomist,
journalist, and author William Evans (artist), Victorian
portrait painter , a
geochemist with the United
States Geological Survey The United
States Geological Survey (USGS) is a scientific agency of
the United States government. The scientists of the USGS study the
landscape of the United States, its natural resources, and the natural
hazards that threaten it. .
Today, gas is still leaking into the lake from the hot rocks
below,
but scientists are taking steps so Lake Nyos doesn't blow again. A
200 meter (656 foot)-long pipe has been placed in the center of the lake
to de-gas its waters (see diagram, right). The pipe spews a continuous
fountain of carbonated water 40 m (131 ft) into the air.
Degassing degassing(dēgas´ing),adj
related to degasification, the process by which dissolved gas is
removed from water or other liquid solutions. is slowly lowering
the C[O.sub.2] levels, making the lake
safe again. But people from the region have not been allowed to return.
"There is still a danger until all the gas is gone," says
Evans.
Volcanic eruptions are most likely in the Pacific Rim states of
Hawaii, Alaska, Washington, Oregon, and California...MOREhere's a link:www.maar.usvolcanoes.usgs.govnotice that most volcanoes in the northwestern
