What are some signs of volcanic activity?
99516
Huge amounts of fiery molten lava hauling butt towards you until it reaches you, and then you combust.
463260
A GPS unit can track ground swelling (especially around active volcanoes).  It relays information about the position of the ground as it changes.\n\nA reading that changes is a definite indicator of change in the ground and could indicate earthquakes or erupions.\n\nAs for plate tectonics, it relays general continental motion (albeit in inches/year)
851419
the gases build up that pushes the molten up, if there is snow causes hazardous and gaseous mud slide down the mountain.  Causes some tremors like earthquakes. Hazardous smoke (ash) cloud.  look up mount saint helens in Washington or the volcanoes in hawaii.  plus there are many throughout south america.  Pictures of mt. st. helens are awesome. I went there after it happened in 1980 it was phenomenal!  I felt the tremors up by bellingham. it was cool.
835536
i am not a seismologist but i think the movement of plates create holes and cracks beneath the crust that may cause the formation of openings where the hot gases and great pressures pass through and for several months or years a violent volcano may explode!
150920
It's a pretty impressive stratovolcano also called Fuji-san. It towers almost 11,500 feet above the surrounding area. The most recent eruption was in 1707 on the southeast side of the cone. That eruption blew out about 0.8 cubic kilometers of volcanic ash. By comparison Mt.St.Helens in 1980 ejected 1.25 cubic km of ash. There have been 16 eruptions recorded since 781 AD. \n\nIt appears from looking at the Global Volcanism Program that there has been no earthquake activity in the volcano since 2001. It seems quiet, but is a young volcano still. \n\nHere is a great collection of Mt Fuji photos:\nhttp://live-fuji.jp/fuji/beste.htm\nHere is a live web cam link of Mt Fuji:\nhttp://live-fuji.jp/fuji/livee.htm
926277
A volcanic event can include\n\n(1) an eruptive pulse (essentially an explosion with an eruption plume, but also non-explosive surges of lava. A pulse may last a few seconds to minutes, \n\n(2) an eruptive phase that may last a few hours to days and consist of numerous eruptive pulses that may alternate between explosions and lava surges, and\n\n(3) a single eruption or eruptive episode, composed of several phases, that may last a few days, months or years (Fisher and Schmincke, 1984). Paricutin, Mexico was in eruption for nine years. Stromboli, Italy has been in eruption for over 2000 years.
305725
Yes, the seismic activity that causes one can also cause the other.  When the Earth's techtonic plates shift but experience some resistance, they shake, jump, rattle the area around that resistance.  Sometimes a crack in the Earth's crust is created or widened which creates the eventual environment for a volcano.  Othertimes volcanoes are created over a hot spot (thin crust) in the Earth's crust, like the Hawaiian islands.  This is somewhat different, although some tremors can be felt.
1183333
Probably through volcanic undersea eruptions.
1089411
You think we are seeing lots of volcanic activity NOW?\n\nRent a copy of Walt Disney's "Fantasia" and watch the part about the early ages of the Earth.\n\nFor millions of years, all this planet DID was erupt.\n\nOf course, your question is tied more to relatively recent times.  The planet seems to pass through periods of greater and lesser volcanic activity.  Much of it is stimulated by movement of the great "tectonic plates" on which our globe is formed.  These are huge chunks of the Earth's crust that slide and bump into one another.  They "float" on top of the more liquid, or molten, components of the Earth's core.\n\nVulcanologists, or specialists in volcanoes, can answer your question with greater precision.  In general, there has been an apparent increase in volcanic activity over the past 40-50 years.  That's how long I've been paying attention, anyhow.  But some of this appearance of activity is a product of remembering volcanic events - a few this year, another one or two some years later, and so on.  Most what I have noticed is that volcanic activity seems to have moved around the world.  Where one volcano goes ka-boom, or squirts out some lava for a time and then goes quiet, later there's a new one doing the same elsewhere.  After a time, it seems there are lava flows everywhere, when in fact there are not.\n\nThe most persistent volcanic activity I can remember is in Hawaii, where for at least 20 years (or so it seems) the Big Island has slowly been growing as a result of constant lava flow.\n\nThe 1800's overall seem to have been far more active in terms of volcanic eruptions and disasters than the past 100 years.  Some of the most horrendous volcanic disasters took place in that century.\n\nWe should remember that ours is not a "quiet" planet, but an ever-active ball of dirt, water and air.  It's an interesting place, eh?
567611
It is a conical youthful active volcano.
450623
go to\nhttp://en.wikipedia.org/wiki/Volcanoe
934962
Here is today's (nov 5) status report on St. Helen's from USGS: [not copyrighted]. \nMOUNT ST. HELENS UPDATE\n\nCurrent Volcano Alert Level WATCH ; Aviation Color Code ORANGE : Growth of the new lava dome inside the crater of Mount St. Helens continues, accompanied by low rates of seismicity, low emissions of steam and volcanic gases, and minor production of ash. During such eruptions, changes in the level of activity can occur over days to months. The eruption could intensify suddenly or with little warning and produce explosions that cause hazardous conditions within several miles of the crater and farther downwind. Small lahars could suddenly descend the Toutle River if triggered by heavy rain or by interaction of hot rocks with snow and ice. These lahars pose a negligible hazard below the Sediment Retention Structure (SRS) but could pose a hazard along the river channel upstream.\n\nPotential ash hazards: Wind forecasts from the National Oceanic and Atmospheric Administration (NOAA), coupled with eruption models, show that any ash clouds rising above the crater rim today would drift eastward.\n\nPotential ash hazards to aviation: Under current eruptive conditions, small, short-lived explosions may produce ash clouds that exceed 30,000 feet in altitude. Ash from such events can travel 100 miles or more downwind.\n\nRecent observations: The volcano is not visible today owing to clouds and heavy rain. Anecdotal reports and signals recorded on acoustic flow monitors on Saturday night suggest that the rains triggered debris flows that descended both the South Fork Toutle River and North Fork Toutle River, but these remain unconfirmed by field checking yet.
465753
http://www.volcano.si.edu/reports/usgs/index.cfm
581208
When there is earthquake around it.\nWhen you start seeing smoke rising.\nWhen you hear a big explosion and see black smoke.\nWhen you see lava coming down it.\n..well, that's the process anyway.
574830
Here you go:\n\nhttp://volcano.und.edu/vwdocs/msh/
890167
volcanoes and earthquakes (faults)
232163
Yahoo search on images of volcanos:\nhttp://img.search.yahoo.com/search/images?fr=slv2-&ei=UTF-8&p=volcano