By studying the type of material and the distribution of sediment, geologists can learn a lot about volcanic activity.
Eruptions can be predicted in several ways:
Tiltmeters are highly sensitive devices used to identify any bulges in the volcano's sides. The increased pressure causes the sides of the volcano to bulge, indicating an eruption may be imminent.
Gas or steam rising from the crater or the appearance of geysers may suggest that an eruption will occur soon.
Seismometers are used to detect vibrations in rocks. These can be caused by movement of magma or cracking of rocks due to increased temperatures, both of which indicate an impending eruption.
For real time monitinrg of the worlds volcanoes see the World Organisation of Volcanic Observatories website
Ireland and Volcanoes
Ireland is not known for its high level volcanic activity in recent history but by studying the landscape volcanoes from hundreds of millions of years ago can be still be seen.
There are a number of extinct volcanoes in Ireland these include Slieve Gullion in County Armagh, Croghan Hill in County Offaly, Mount Slemish in County Antrim, Lambay Island in Dublin and Loch Na Fooey in County Galway. These volcanoes are all extinct with the last eruption was approximately 60 million years ago.
Today the Geological Survey continues to identify previously undiscovered volcanoes hidden beneath the surface of Ireland. To learn more about these Geophysical surveys visit the Tellus page.
Other volcanic activity can also be identified here in Ireland. One of the world’s most famous Geoheritage sites The Giant’s Causeway, is a result of volcanic activity. Approximately 60 million years ago Antrim was at the heart of intense volcanic activity, magma from below the Earth’s surface forced its way up through fissures in the rock and formed a huge lava plateau. As this lava rapidly cooled it contracted forming the famous hexagonal columns.
To learn more on the Giant’s causeway website.
Hi Will! I appreciated your description of the warning signs of a volcano about to erupt, as well as the use of seismometers to detect vibrations. I have seen images of it before, so it is interesting to learn more about the "Giant's Causeway" and its connection to volcanic activity! While my chosen country of Israel does not have any true volcanoes within its borders, there are volcanic fields and activity located in the countries surrounding it, therefore it is interesting to learn about volcanoes from long ago in your post!
ReplyDelete