Our blog is currently undergoing a change of image. Please bear with us whilst we fix it. It will be back looking better than ever in no time, but we appreciate your patience whilst we upgrade.
Whilst you wait, are you following us on twitter?
Search @bsgeography or see our twitter widget to the right
There is an excellent site set up where you can watch a live expedition to an undersea area of the ring of fire. There is plenty of video available and maps of the area.
There is a live video feed of the expedition as well.
J.Stroomer has produced this excellent study on the causes of the eruption at Mt St helens in 1980:
Mt. St. Helens is a composite volcano within the Cascade Range in southern Washington, approximately 50 miles northwest of Portland, Oregon. Though Mt. St. Helens is approximately 40,000-years old, it is considered a relatively young, active volcano. The Juan de Fuca plate is converging with the North American Plate. The lava forms as the oceanic crust is subducted under the continental crust at the convergent plate boundary.
The eruption on May 18th 1980 is the biggest that it has ever experienced. The build-up to the eruption was a two-month series of earthquakes and steam-venting episodes, caused by an inflowing of magma at shallow depth below the volcano that created a huge bulge on Mount St. Helens' north slope. This s called a cryptodome and can be seen on the images below, it makes a striking impact on the side of the volcano. The scientists and geologists studying the area say
that in the weeks leading up to the eruption it was expanding at a rate of 6ft a day in some places of the dome.
An earthquake, measuring at 4.2 on the Richter scale, at 8:32:17 a.m. caused the entire weakened north face to slide away, exposing the partly molten, gas rich rock in the volcano to lower pressure. This resulted in a landslide where more than half a cubic mile of material was released. This can be seen in the diagram below.
A lot of pressure had built up as this was the first eruption for 123 years. Although it was not without warning, on March 25th the seismographs started to climax at about noon reaching peak levels on the next two days, including one earthquake that measured 5.1 on the Richter scale. A total of 174 shocks, of magnitude 2.6 or greater, in the following two days. This then continued through April and May with 5 earthquakes above magnitude 4 or greater per day in April. This then increased to 8 per day the week before May 18th. There is a before and after shot below to show the impact on the landscape.
This year's upepr sixth are running blog this term on earth hazards as a means of engaging in the course and creating a useful resource for both themselves and others. they have started off with fundamental definitions for hazardous events and useful resources to support that. Keep an eye on it in the feeds to the right as it grows this term....
There was an earthquake close to Costa Rica this afternoon. See what information you can find out about the event using some of the internet sources in this presentation and under the latest news tab to the right:
This is a very impressive video about 2 sisters and their response to a Tornado in their home town. As you watch, consider the following questions: would their technology be appropriate in all areas of the globe? Will there always be donations/volunteers? What enabled them and others to respond successfully?
The UNDP have a campaign on to increase preparedeness and spending on disasters to reduce their developmental effects and spending in the long run. Have a look at the video below which is part of their campaign but als o highlights the issues excellently for those in the upper sixth and year ten particularly this term.
