Fresh vegetables thanks to volcanoes

Thanks to volcanoes, vegetables can be kept fresher. Yes, those that make it possible are the vents, small openings between volcanic rocks through which a slight current of air at around 12°C flows all year round, but with more force during the summer. The farmhouses, and the farmers who worked all day in the garden, used the vents as cool storage.

At Mas Bufador Vell (Olot) there is a large semi-underground chamber fed by a system of vents. In the middle of summer, you need to go in wrapped up warm! Some stallholders from Olot market rented this cellar to store food until the mid-20th century. This is one of the many benefits of volcanoes. There are many more: they provide rock for building, fertile soil...

In La Garrotxa there are a few examples that show that volcanic soil is very fertile. This is the case with the Santa Pau beans, white, small and round, with a very mild taste. And with La Fageda d’en Jordà, which grows on a hard and rugged lava flow that is very difficult to till.

I have arranged to meet Isaac Camps, a geologist and scientific editor, author of the hiking guide Volcanoes of Catalonia, to climb Montsacopa volcano – it is called this because at its summit there is a hollow or "cup": it is the crater. It is one of the youngest volcanoes in the region, it is "only" 20,500 years old. It has an elongated shape, like an espadrille. Like the other volcanoes in La Garrotxa, it is monogenetic, meaning "made in one go": it erupted one fine day, was active with more or less virulence for a period (days? months?) and stopped indefinitely. In contrast, polygenetic volcanoes, of larger volume, are active for hundreds of thousands or even millions of years, such as Teide or Fuji.

As we climb Montsacopa, a ten-minute walk, we see on both sides of the path small porous stones, which here are called greda or tosca. "Can these stones become lava again?", asks Fàtima, the youngest of the family, 12 years old, who is accompanying me today. Children are naturally inquisitive, and she is no exception. Asking questions is the gateway to knowledge. "Yes, but they would need to be in an oven at about 700 degrees Celsius for them to start melting", replies Isaac. "Wow, that's a lot!", exclaims Fàtima. "Think that the tip of a cigarette when you take a puff can reach 950 degrees", Isaac clarifies.

I'm interested in more practical things. "Could this volcano erupt again?", I ask. "Not this one. But an eruption in the region can't be ruled out in the future", they reply. "We have dormant volcanism, but not extinct", they add, and the word vulcanism... sticks with me – with a 'u', of course, but shouldn't it be with an 'o' if it comes from 'volcano'? Language quirks. u, of course, but shouldn't it be with an o if it comes from volcano? Language quirks.

"Can a volcanic eruption be predicted?". "Yes, more and more. Areas with volcanic risk, and this is the case, are monitored: the small tremors generated by magma as it rises are listened to, changes in gases emanating from the subsoil are analyzed... If done correctly, this would provide enough time to evacuate".

"It looks like King's coal!", says Fàtima, observing a reddish scoria (it's this color closest to the volcanic conduit; the black ones, on the other hand, are those that fall further away).

We are now inside the crater. "It used to be deeper and steeper. It is said that the children of Olot used to come to play here, to slide with carts and do somersaults. Agricultural activity – it used to be cultivated in the crater – and the erosion of the slopes have been filling it with sediment and have given it its current shape".

Walking around the top of the volcano, we recognize a few neighborhoods of Olot. We have in sight that of Sant Pere Màrtir, with simple white houses, a small garden and a porch, built in the early 1950s. It was created, in part, to accommodate immigration from the region who came to work in textiles. We also see the large plain of the Vall d'en Bas, which was created by volcanoes: the lava blocked the Fluvià river, it dammed up and formed a large lake.

Then Isaac shows me a laminated sheet. It is a drawing that appears in Principles of Geology, a foundational book of modern geology. It is a drawing of Olot showing its three volcanoes: Montolibet, Montsacopa, and La Garrinada. Now there are more houses and more forest, of course. The drawing was made by the Scotsman Charles Lyell, "father of modern geology". In the summer of 1830, Lyell wanted to see the volcanoes of Olot and took a trip on the back of a mule. He visited not only La Garrotxa, but also many other places in Catalonia.

We descend along a paved track, where there is a Way of the Cross. At the foot of the Montsacopa volcano is Espai Cràter, a new museum (opened in 2022, post-pandemic, therefore), built within Puig del Roser, a kind of small volcano. It is my second objective for today. It is worth visiting just to see the semi-underground building, designed by architects Anna Codina and Toni Casamor, of VOL Studio Architecture. The entire building resembles a volcano.

Espai Cràter explains in a very didactic way – better than when they explained it to me at school; progress has been made in this regard – how the volcano works, what types of volcanoes there are... It does not forget local information, for example the campaign "Save the Volcanoes", which originated in La Garrotxa in the 70s. For many years, trucks took tons and tons of marl for construction. Some of the excavated holes became landfills. Fortunately, all this has changed. It is now strictly forbidden to put a volcanic stone in your pocket.

Bridges, churches, walls, and houses built with volcanic stoneThe volcanoes of La Garrotxa provided marl and basalt for centuries, very versatile materials that were used to build bridges, churches, walls, and houses. This traditional use gave rise to a distinctive, dark, and robust architecture. There are also huts and shacks made of volcanic stone.