Case Study: Soufrière Hills, Montserrat

Hey guys, Thought i'd do a case study, just for fun. I know i havent posted alot. And thats because i start writing a post then think of another idea and start on that instead! so currently, im writing about a dozen posts at once, so there will be plenty later on. So without further ado, Montserrat...

Around the Caribbean lies the chain of islands known as the Lesser Antilles. These small islands were all created at the destructive convergent plate margin of the Atlantic and Carribean Plates, causing mountainous islands to spring up along the boundary. On a destructive boundary, one plate subducts under the other, causing the one that is being pushed down to melt. When this happens, the magma, usually rich in atmospheric gases, will be lighter than the resot of the lithospheric magma, meaning it will rise up and sprout up on the crust in the form of volcanoes. Thier lava is felsic, meaning the silica, sticky in texture, makes the lava/magma very vicous, creating very violent eruptions when pressure builds inside. This is the case on thesmall island of Montserrat, a small British colony, only 102-squared km in area. Originally used for plantations, the island is now known for the music recording business. With such a small number of inhabitants (less than 12,000), Montserrat keeps the sky and sands a beautiful tropical land. The biodiversity all links back to the lush soil, created by the massive Stratovolcano towering over the island. Though it had been dormant for over 370 years, it was obvious that the volcano was still alive, seen by indicators like the springs, so hot they could boil an egg.

Soufriere Hills is so large that 80% of Montserrat’s population lives in the shadow of the volcano. For centuries the volcano hadn’t shown any signs of erupting back to life, and people weren’t scared. In the years leading up to the end of its dormancy, there were many signs. Such as the minor earthquakes felt in the area that had first been seen back in the 1930, 30 years later in the 60's it tried to erupt again, with even bigger earthquakes. Third times the charm for Soufriere Hills, for in the summer of 1995 Soufriere Hills began to rumble. For days this sound continued, resembling a jet engine. When it finally erupted it was a phreatic explosion (water in the crater being heated), though not as bad as a full-scale quake still caused Lahars and pyroclastic flows. They covered the villages with mounds of debris from the pyroclastics and buried many houses and farmlands in the way. When these began to occur more frequently volcanologists and other scientists came and set up the Montserrat Volcano Observatory. In time, these eruptions began to effect the people. With the majority of the population living in its path, including the capital Plymouth, people began to think about leaving to somewhere safer. But it was not until June the 25th of 1997 that Soufriere Hills unleashed its mightiest blow yet…

Throughout the night of the 24th earthquakes could be felt.

7:00 AM – It was visible that the crater was beginning to swell under pressure as magma pushed its way up.

12:45 – the sirens in Plymouth begin to sound, warning people to run. The dome begins to deflate.

12:55 – the dome breaks unleashing masses of lava everywhere. Immediately pyroclastic flows swept down Mosquito Ghaut, obliterating anything in the way.

1.08 - 3rd Pyroclastic flow is released.

1:10 PM – Rescue crews begin to show up. 4 were confirmed dead with 17 missing.

What caught the islanders by surprise was the fact that beforehand they had cleared exclusion zones, but the force of the 1997 eruption was so big that it went way into these areas. To add on to this, the flows werent even predicted to make is out of the valley in the first place let alone to the exclusion zones. In the end 19 people were confirmed to be dead with over 150 houses destroyed. While in the past, smaller eruptions released one pyroclstic flow, this one let out three, each time getting bigger, faster, and more powerful, all moving in different directions, increasing th area of destruction. Lahars and landslide were shook free, lets to make its way down Chance's Peak.

Primary Impacts

- 19 people dead (mainly from pyroclastic flow)

- Plymouth's (capital) airport and hospital were destroyed

- Towns were buried in several meters of ash and debris

- fires caught to the forests around the island becuase of the pyroclastic flow

- ash suffocated the environment

Secondary Impacts

- The destruction of the farmlands meant any exporting of goods had to stop

- The tourist industry, where much of thier money came from failed as there was nothing left to see and people were scared.

- The loss of the airport meant there wasno easy way to get out.

- 150 houses detroyed

- Being in an undeveloped place, it was harder for them to rebuild, even with British investments

- Water pipes and sewerage broke and mized in with the poisonous material from pyroclastic flow, casuing disease and sanitary problems.

- Any farm animals were suffocated

- The overall workforce was lessend as those who had escaped the island before it blew didnt want to come back in fear of the volcano and loss of thier homes.

- pollution of the waters in and around the island from debris and rise in acidity.

Predictions to the 'awakening' of Soufriere Hills such as the visual deformation of the ground and the increase in seismic activity. Three years before the first phreatic eruption occured, earthquakes struck the island hard. Once it began acting up in 1995, the observatory took action before any major events by starting to evacuate people to the North of Montserrat as well as other islands close by. This saved many lives. Though many people refused as the farm land on the island were nessesary for thier income. After the 1997 eruption, the British government immediatly acted to help the colony by funding reconstruction and redevelopment in the North (41 million bp). This meant infrastructure was improved in the North. A larger exclusion zone was set up. Now that the population was at a mere 4,000 people, it was harder to get the economy moving again. Though the tourist industry had stopped for a while after the eruption, the active volcano meant that many people came to the island to see it.

Thanks for reading!

Sabrina :)

#volcano #earth #Montserrat #phreatic #sulfur #pyroclastic #ash #eruption