In 1997, an eruption occurred in the Soufriere Hills and engulfed the town of Plymouth on the island of Montserrat. The capital, once a bustling center for commerce, was covered with several feet of ash and debris in a matter of hours, necessitating permanent evacuation. The Montserrat Volcano Observatory says the eruption destroyed more than 80 percent of Plymouth’s infrastructure. Even though Plymouth is now a deserted exclusion zone, it is still legally the capital of the island today. The city has been compared to a ‘modern Pompeii’ and is a reminder of the devastating effects of geology; It has also provided scientists with valuable information about how volcanoes affected and displaced modern civilization over time.
How Soufriere Hills Volcano wiped plymouth off the map
The destruction of Plymouth was caused primarily by pyroclastic density currents (PDCs) – gravity-driven clouds of hot gas and rock. Research published by the U.S. Geological Survey (USGS) and the Montserrat Volcano Observatory (MVO) indicates that these flows reached temperatures in excess of 400 °C (752 °F) and traveled at speeds in excess of 100 mph. PDC flows behaved like fast-moving fluids, and due to the fluid nature of these high-velocity streams, they were able to completely cover buildings from their base to the second floor with a densely packed matrix of fine ash and tephra. In doing so, this quick burial preserved the Plymouth in a frozen state, thus providing archaeologists the opportunity to study the ashes and volcanic soil from everyday objects of 20th century life. These artifacts represent a unique, but fragile means by which archaeologists will gain knowledge about life in the Caribbean during the 20th century.
How does the MVO monitor structural decay in the restricted area?
Plymouth, the (legal) capital of Montserrat, has been destroyed along with all of the city’s infrastructure. However, the Government of Montserrat maintains that although the government has moved its administrative functions to the north of Brades Island, Plymouth’s legal status as the official seat of government is still preserved in the constitution and other records. The southern half of Montserrat is designated as Zone V exclusion zone and cannot be entered without police escort due to the constant danger from the volcano. This ongoing and complete legal and physical isolation of the city allows the Montserrat Volcano Observatory (MVO) to use GPS and seismic sensors to study accelerated structural failure and corrosive loading from the weight and chemical acidity of volcanic tephra.
How volcanic tephra reshaped Montserrat’s topography
According to research in the Journal of the Geological Society, the large amount of volcanic material deposited in Plymouth permanently reconfigured the island’s topography and expanded its coastline. Layers of ash, more than 12 meters (39 ft) thick in some areas, have altered the island’s drainage basin and coastline. In addition, the high porosity of volcanic tephra acts as a thermal insulator; Therefore, combined with the lack of light, this creates a slow decay rate for all organic materials and household artifacts that may be buried beneath it.Based on data from NASA Earth Observatory, these environmental changes have produced specialized pioneer plant species in the exclusion zone and provide a unique model of biological succession in post-eruptive tropical environments.