NH
Natural Hazards

Archives / 2019 / October

The bad, the good and the unpredictable: living with volcanoes / part 1

The bad, the good and the unpredictable: living with volcanoes     / part 1
Introduction

Humans have existed and lived alongside volcanoes for as long as we have been on the planet. For some, this has been beneficial and often, in fact, we can see how indigenous knowledge finds a sustainable approach living with them. However, in some cases, societies cannot cope and are overwhelmed with volcanic eruptions. 

There are many examples from archaeological studies dealing with how ancient civilisations, successfully or unsuccessfully, lived with volcanoes. On one hand, for example, Pre-Colombian villages in Costa Rica were found to be the most resilient to the eruptions of Arenal volcano, managing to cope and survive with many eruptions. The villages were simple societies with egalitarian rules (where people are viewed as having equal rights and opportunities). This meant that they coped faster because everyone had the same duties and rights and were able to help each other without waiting for a ruler to do something for them. On the other hand, more complex chiefdoms in Central America struggled to cope with these events as they had a greater reliance on the built environment, competitive and sometimes hostile political environments and greater population densities [1, 2]. 

[Read More]

How can remote sensing and wavelet transform unravel natural and anthropogenic ground motion processes?

How can remote sensing and wavelet transform unravel natural and anthropogenic ground motion processes?

Underground energy storage and gas storage in aquifers

In the context of energy transition, massive energy storage is a key issue for the integration of renewable sources into the energy mix. Storing energy in the underground can lead to larger-scale, longer-term and safer solutions than above-ground energy storage technologies. In particular, natural gas storages are designed to address different needs, like a strategic natural gas reserve, the regulation of gas supply and the answer to a seasonal peak heating or electricity demand. Energy companies routinely store gas in underground reservoirs known as “gas aquifers”, which then become gigantic natural tanks for injecting and extracting gases for energy needs. The natural gas is compressed and injected through wells into selected reservoirs, usually constituted of sand layers containing water, which is automatically forced out. The gas is then extracted from the same wells and the water can naturally flow back into the sand, maintaining equilibrium. Natural gas is stored from May to September when the demand is lower and withdrawn from October to April when the demand is higher.

Figure 1 – Location map showing a Sentinel-1 acquisition (2016) in Southwestern France (Aquitaine Basin) (colour image), a 25 km cell used by SMOS satellite (black square) that contains the reservoir isobaths of a gas storage site (red lines).

Integrated monitoring of a gas storage site

For risk prevention and environmental protection purposes, it is essential to check the integrity of the natural reservoirs used for underground storage and how they respond to the annual natural gas injection and extraction cycles. [Read More]