A MULTI-CRITERIA VULNERABILITY ANALYSIS APPLIED UNDER THE DISASTER RECOVERY FRAMEWORK AFTER THE TAJOGAITE'S VOLCANIC ERUPTION IN LA PALMA

The vulnerability is one of the critical factors on disaster risk reduction. It plays a central role in the risk analysis. After the volcanic eruption that took place in La Palma island in September 2021, a Post Disaster Need Assessment (PDNA) have been promoted to develop a suitable recovery strategy. One of the cross-cutting themes included in the PDNA are the disaster risk reduction actions, where the risk analysis becomes crucial to establish measures to reduce, prevent and adapt from future impacts. In this regard, different experts started to develop a process for identifying and assessing hazards such as volcanic hazards, floods, landslides and earthquakes. However, the data, tools and method for assessing vulnerability were unresolved. In order to fill this gap a vulnerability assessment centred on indicator-based methodologies was applied. It consists on a semi-quantitative methodology that seeks to integrate the vulnerability variables using a weighted multicriteria analysis. The characteristics of the population, buildings, the road system, crops and the main infrastructures and services have been evaluated. As unit of analysis the Eurostat statistical grid was used, as it is available for all Europe and adapted to the Canary Islands with cells of 250m on each side. An additional method was applied in order to simulate the vulnerability on projected urban developments in areas currently destroyed and occupied by lava.

As a result of this integrated analysis, 10% of the island has high or very high levels of vulnerability. The capital region (or Southeast) is the most vulnerable (13.74% with a high level) followed by the Aridane Valley region (or Southwest) (9.26%). These two regions are home to the 80% of the island's population and where the main urban centers are located in. Therefore, most of the infrastructure, services and economic activities are also placed there. This makes these sectors very vulnerable due to their insular importance and high exposure. On the other hand, the northwest sector is where we found the lowest vulnerability (7.34%), where the high values are mainly due to the aging of the population and the age of the buildings.

It should be noted that the results obtained have a detailed analysis scale suitable for carrying out territorial planning exercises. They also allow us to assume and integrate hazard intensities and probabilities for risk analysis in subsequent studies. Finally, the theoretical-methodological approach proposed could be applied and replicated in other territorial areas with similar characteristics to those proposed.