Popular classification of volcanoes Volcano

1 popular classification of volcanoes

1.1 active
1.2 extinct
1.3 dormant , reactivated

popular classification of volcanoes

a popular way of classifying magmatic volcanoes frequency of eruption, erupt regularly called active, have erupted in historical times quiet called dormant or inactive, , have not erupted in historical times called extinct. however, these popular classifications—extinct in particular—are practically meaningless scientists. use classifications refer particular volcano s formative , eruptive processes , resulting shapes, explained above.

active

there no consensus among volcanologists on how define active volcano. lifespan of volcano can vary months several million years, making such distinction meaningless when compared lifespans of humans or civilizations. example, many of earth s volcanoes have erupted dozens of times in past few thousand years not showing signs of eruption. given long lifespan of such volcanoes, active. human lifespans, however, not.

scientists consider volcano erupting or erupt if erupting, or showing signs of unrest such unusual earthquake activity or significant new gas emissions. scientists consider volcano active if has erupted in last 10,000 years (holocene times) – smithsonian global volcanism program uses definition of active. volcanoes situated on pacific ring of fire. estimated 500 million people live near active volcanoes.

historical time (or recorded history) timeframe active. catalogue of active volcanoes of world, published international association of volcanology, uses definition, there more 500 active volcanoes. however, span of recorded history differs region region. in china , mediterranean, reaches 3,000 years, in pacific northwest of united states , canada, reaches less 300 years, , in hawaii , new zealand, around 200 years.

kīlauea lava entering sea.



lava flows @ holuhraun, iceland, september 2014

as of 2013, following considered earth s active volcanoes:

kīlauea, famous hawaiian volcano, has been in continuous, effusive eruption (in lava steadily flows onto ground) since 1983 , has longest-observed lava lake.
mount etna , nearby stromboli, 2 mediterranean volcanoes in continuous eruption since antiquity.
mount yasur, in vanuatu, has been erupting continuously on 800 years.

as of august 2013, longest ongoing (but not continuous) volcanic eruptive phases are:

mount yasur, 111 years
mount etna, 109 years
stromboli, 108 years
santa maría, 101 years
sangay, 94 years

other active volcanoes include:

mount nyiragongo , neighbor, nyamuragira, africa s active volcanoes

nyiragongo s lava lake


.
piton de la fournaise, in réunion, erupts enough tourist attraction.
erta ale, in afar triangle, has maintained lava lake since @ least 1906.
mount erebus, in antarctica, has maintained lava lake since @ least 1972.
mount merapi
whakaari / white island, has been in continuous state of smoking since discovery in 1769.
ol doinyo lengai
ambrym
arenal volcano
pacaya
klyuchevskaya sopka
sheveluch

extinct


fourpeaked volcano, alaska, in september 2006 after being thought extinct on 10,000 years



mount rinjani eruption in 1994, in lombok, indonesia

extinct volcanoes scientists consider unlikely erupt again because volcano no longer has magma supply. examples of extinct volcanoes many volcanoes on hawaiian – emperor seamount chain in pacific ocean (although volcanoes on island of hawaii active), hohentwiel in germany, shiprock in new mexico, , zuidwal volcano in netherlands. edinburgh castle in scotland famously located atop extinct volcano. otherwise, whether volcano extinct difficult determine. since supervolcano calderas can have eruptive lifespans measured in millions of years, caldera has not produced eruption in tens of thousands of years considered dormant instead of extinct. volcanologists refer extinct volcanoes inactive, though term more commonly used dormant volcanoes once thought extinct.

dormant , reactivated


narcondam island, india, classified dormant volcano geological survey of india

it difficult distinguish extinct volcano dormant (inactive) one. volcanoes considered extinct if there no written records of activity. nevertheless, volcanoes may remain dormant long period of time. example, yellowstone has repose/recharge period of around 700,000 years, , toba of around 380,000 years. vesuvius described roman writers having been covered gardens , vineyards before eruption of 79 ce, destroyed towns of herculaneum , pompeii. before catastrophic eruption of 1991, pinatubo inconspicuous volcano, unknown people in surrounding areas. 2 other examples long-dormant soufrière hills volcano on island of montserrat, thought extinct before activity resumed in 1995, , fourpeaked mountain in alaska, which, before september 2006 eruption, had not erupted since before 8000 bce , had long been thought extinct. climate change can reportedly trigger volcanic activity in sensitive areas changing pressure of ice or seawater , extreme weather.