For an explanation, see the main splats page
The principles of volcanoes
- Volcanoes bring molten rock to the surface, erosion and weathering convert these rocks to sediments. If they are compressed or heated, sedimentary rocks change.
- A volcano erupts when magma gets close enough to the surface of the Earth to force its way out: when it erupts onto the surface, the molten rock is called lava.
- Volcanoes are of different types, determined by the sort of magma that is working its way to the surface, as the geochemistry influences the type of eruption.
- Volcanoes happen where plates are in contact, and also over 'hot spots' which can cause a chain of volcanoes as a plate moves over the hot spot.
- Many of the volcanic island chains in the Pacific Ocean are caused by a plate moving over a hot spot. Hawaii is probably the best-known example.
- Volcanic areas often have geysers, where groundwater is heated under pressure until it boils, pushes out overlying water, and then boils explosively.
- While volcanoes cause a great deal of local damage in the short term, they are very useful in long term because they bring valuable new minerals to the surface.
- Volcanoes produce more than lava flows: they also produce large clouds of ash and dust which can travel long distances, and large amounts of noxious gases.
- The form and shape of a volcano depends on the chemical composition of the magma which determines how it erupts.
This file is http://members.ozemail.com.au/~macinnis/scifun/, first created on February 23, 2009. Last recorded revision (well I get lazy and forget sometimes!) was on February 23, 2009.
©The author of this work is Peter Macinnis, who asserts his sole right to the product as it is packaged here, recognising that many of the ideas are common. You are free to use this as a model to do your own version. Copies of this whole file or site may be made and stored or printed for personal or educational use. You can contact me at firstname.lastname@example.org, but only if you add my first name to the front of that email address -- this is a low-tech way of making it harder to harvest the e-mail address I actually read.
This site had 219,000 hits on the index page from 1999 to January 2007 and an unknown number on other pages. In January 2007, a combined counter was placed on all of the pages, counting page hits which now total