Case Study: Monserrat Volcanic eruptions

Case Study: Monserrat Volcanic eruptions

Case Study: Montserrat Volcanic Eruptions

General Information

Before 1995 the population of the British colony of Montserrat was 11000 people. On the island the Soufriere hills volcano was dormant for 400 years. On July 18th, 1995 the volcano awoke, blowing large clouds of ash and steam in the air in the eruption. Two-thirds of the island was abandoned, 8000 people have left the island, the ones who have stayed moved to the northern safe zone. Everyone lived near the volcano.

Situation

The volcano lies over a destructive plate margin. The North American plate is sinking under the Caribbean plate. This plate margin formed the Antilles –Seen on Appendix A). The volcano is a strato volcano.

Hazards

On Montserrat there were no lava flows the biggest threats were pyroclastic flows. Such occur at the event of a dome collapse, or explosion. The pyroclastic flow moves at a speed over 160 km/h and a temperature over 400C. Also on Montserrat not only volcanoes are the only hazards, but hurricanes are a regular threat too.

Hazard Management

On Montserrat there is an initial seismic activity monitoring system. Also the Montserrat Volcano Observatory was established to coordinate monitoring of the volcano and to advise the Governor of Montserrat. For more support the USGS‘s response was their Volcano Assistance Program (VDAP). The purpose of this is that the VDAP is always ready to assist with volcanic monitoring in countries that do not have sufficient resources to do so.

Precautions done:

- Extensive seismograph system is placed on the volcano to measure earthquake strength and depth
- Earth deformation meters are placed near/on the volcano to see if the earth is changing in any way i.e. swelling or deflating as magma moves.
- GPS is used to see if there is any ground movements
- COSPEC was installed to check for volcanic gases, particularly sulphur-dioxide, this is a good sign of magma movement
- The pH of rainwater is monitored too,...