Understanding Risk
Preliminary Concepts about Volcanic Risk
Some individuals may use the terms “hazard” and “risk” interchangeably, which can lead to misunderstandings when interpreting scientific information.
From a scientific standpoint, one internationally recognized definition of natural risk, commonly used in volcanology, is the result of exposure (expressed as the number of people or monetary value), vulnerability (indicating the expected damage to the exposed element), and natural hazard (intensity of the natural phenomenon or probability of its occurrence). Therefore, when scientists refer to hazard, they are focused solely on the natural phenomena, without considering their interaction with the built environment or the expected impact.
Our section dedicated to Hazard Assessment is focused on understanding the volcanic hazards posed by the Soufrière Hills, while this section is dedicated to understanding their impact.
Volcanic Risk Management encompasses all knowledge, measures, and communication systems that provide appropriate advice to make informed decisions aimed at reducing risks. It is a comprehensive system where personnel from scientific and public institutions collaborate with members of the exposed community to mitigate expected impacts. Every individual and measure within this system should be interconnected, and inappropriate usability may compromise the overall functionality of the system.
In Montserrat, the technical institution responsible for understanding and monitoring volcanic activity is the Montserrat Volcano Observatory. Decision-making is overseen by the HM Governor of Montserrat and the Disaster Management Coordination Agency (DMCA).
The primary tools utilized include the Montserrat Hazard Level System Zones (see our Hazard Assessment section for more information), an emergency system comprising sirens placed strategically, and control doors regulating access to hazard zones. These tools are bolstered by continuous communication among institutions, the periodic issue of volcanic activity level, and mandatory evacuation plans necessary for conducting economic activities in the hazard zones.
Montserrat Pre-eruption
This map displays a 3D interactive perspective of the 1995 Digital Elevation Model, along with the main populated areas in the South of Montserrat before the onset of the Soufrière Hills Volcano eruption. The aerial images depicting the populated areas were captured during aerial flights on March 16, 21, and 25, 1991, and are locally available at the Montserrat National Trust Archive.
The buildings and road transportation have been converted into Geographical Information System layers, represented as extruded blocks or linear features. Refer to the legend below to better understand the color representation differences. This geographic layer can be toggled using the layer tool available on the top-right side of the map.
To understand the level of exposure in the South of Montserrat, the layer tool mentioned previously also includes various geographic layers representing the main volcanic hazards emitted by the Soufrière Hills Volcano. These geographic layers highlight the most relevant areas impacted by these hazards since 1995. For further information about Soufrière Hills Volcano’s hazards, you can navigate to the Hazard Assessment page.
Open Visualization Tools:
Show 3D view of hazard map or see below
Show pdf version of hazard map
Legend of 1991 3D-Map
Montserrat Post-Eruption
This map presents a 3D interactive perspective of the 2014 Digital Elevation Model, along with the most recent view of the South of Montserrat in 2022, facilitated by the Google Satellite imagery accessed using the Quick Map Service Plugin in QGIS.
Same geographic layer representing buildings and road transportation are shown here, but using a different color scale. Refer to the legend below to better understand the color representation differences.
The colors in the building geographic layer represent the status of the roof of each building, determined through remote analysis using a sequence of images covering 1991, 2003, 2010, and 2022. While this analysis lacks the accuracy provided by fieldwork, it serves as a guide to understanding the impact suffered in various locations over time.
This geographic layer can also be toggled using the layer tool available on the top-right side of the map. In some areas, however, it may be difficult to see the buildings due to the significant development of vegetation, or because they were buried or swept away.
Similar to the 1991 3D map, the layer tool mentioned previously also includes various geographic layers representing the main volcanic hazards emitted by the Soufrière Hills Volcano. However, in this case, both the hazard information and the image shown in combination illustrate the changes undergone by the territory since 1995. For further information about Soufrière Hills Volcano’s hazards, you can navigate to the Hazard Assessment page.
Open Visualization Tools:
Show 3D view of hazard map or see below
Show pdf version of hazard map
Based on the remote assesment of the status of each buildig and the classification we made, here we present son preliminary statistic organized by village and hazard zones. It must be said that due the long period of time lapsed since the area was evacuated, most of the building still in place have not receive any care or improvement, so the internal damage in their structure and cover material is significative. Although our approach do not consider such detailed analysis, it can be useful to understand the spatial variation in the level of the volcanic hazard intensity recieved since 1995, which is our main purpose.
Legend of 2022 3D-Map
