Stunning São Miguel illustrates prowess of volcanoes

Many miradouros [lookout points] atop São Miguel’s heights let us study reminders of the mighty formative powers of volcanoes: steep-walled calderas, black-sand beaches with craggy lava boulders, billowing steam from fumaroles, and verdant greenery from fertile volcanic soil.

We spent a week on São Miguel – the largest of the nine islands in the Portuguese archipelago of the Azores. It’s so stunningly gorgeous and peaceful that it’s tempting to overlook the island’s oozing rumbly past. But the evidence is right there before you: volcanoes formed these islands just a blink of an eye ago, geologically speaking. The islands sit at the junction of three tectonic plates – the Eurasian, North American, and African – hence the seismic and volcanic activity. São Miguel’s last eruption was in 1652.

Scientists closely monitor all the rumblings; I knew we’d have enough warning of any impending disaster. So I set that worry to the back of my mind and thoroughly enjoyed exploring São Miguel. At just 62 kilometres long by 15.8 kilometres wide at its maximum width, it’s not a huge island but there’s much to see.

Sete Cidades caldera

Several miradouros [look-outs] offered different angles on the lakes within the Sete Cidades caldera. We hiked along the steep-sided rim, looking down into the caldera on one side and out to the Atlantic Ocean on the other.

The Sete Cidades caldera at the west end of São Miguel is the most popular sight. And for good reason: the views over the lakes within the caldera are postcard-perfect.

Starting at the Boca do Inferno [Mouth of Hell] miradouro, we hiked along a descending ridgeline (see top photo) to a railed viewpoint. The panorama included the distant village of Sete Cidades, completely within the caldera on the shore of Blue Lake. In front of that was a smaller caldera within the larger Sete Cidades caldera – evidence of the tens of thousands of years of volcanic activity that has resulted in the Russian-doll-like series of nesting calderas, lakes and pointy volcanic cones.

Next was the Vista do Rei [King’s View], named in honour of King Carlos and Queen Amélia who visited in 1901. That’s where you see the famous hour-glass-shaped lakes called the Blue Lake and Green Lake, separated by a bridge. The twin lakes often have distinctly different colours – hence their names. Legend says the colours come from the tears of a blue-eyed shepherd and a green-eyed princess whose love was forbidden. Science says the colours come from light reflecting off differing levels of phytoplankton in the water. We’d seen photos of the different colours, but both lakes looked dark blue on the day we visited. Regardless, the view is gorgeous. 

Starting at the Vista do Rei, we hiked along the steep-sided western rim of the caldera. Tall hydrangeas – up to nine feet high – with head-sized blooms lined the right-hand side. But somebody had hacked back the vegetation in spots to create windows, so we could look down into the caldera. Cows grazed in sloped pastures and farmers harvested corn.

On the left-hand side, we saw the Atlantic Ocean, edged with turquoise water and foamy white waves dashing against black lava boulders. We could have kept going, since the trail leads down into the village of Sete Cidades, but we turned around after 3.5 kilometres and retraced our steps to the Vista do Rei.

Driving down from the viewpoints into the village, we stopped at the bridge to study the twin lakes up close, but they still seemed the same colour.

On the way to Sete Cidades, we stopped to see sections of old aqueducts, built in the 1500s and 1800s.

Just off the road leading to Sete Cidades, we stopped to investigate the ruins of two aqueducts, built to carry water from nearby lakes into Ponta Delgada, São Miguel’s main town. The black rock – I assumed it was volcanic – was richly ornamented in green mosses, ferns and orange lichens. A two-storey section called Muro das Nove Janelas [Wall of Nine Windows] was built in 1521.

Lava-tube cave

We descended into the belly of the beast – a lava tube cave. I stuck my head into one lava formation that looked like a T-Rex mouth with stalactite teeth. A curious plastic-looking coating on a rock was another form of volcanic rock that’s smooth and glass-like.

We got the inside scoop on São Miguel’s volcanoes at Gruta do Carvão – the largest lava tube cave on the island.

“You’re going to literally walk on lava – solidified, of course,” said our tour guide, Rodrigo.

We descended into the belly of the beast, stepping ever so carefully over sharp lumps of lava on the cave floor and ducking our heads under small stalactites that tested our helmets. We picked up rocks just to feel their lightness.

The cave was a river of lava about 5,000 years ago. The top solidified into a crust of basalt, but the lava kept flowing inside, draining into the ocean four kilometres away. What’s left is the tube that we explored. One big cavern was formed when lava exploded upwards, creating a second level above.

“There’s a 99.9 percent chance there’ll be no eruption today,” Rodrigo said. “And lava flows slowly so you’d still have time to take photos.”

Furnas fumaroles, geysers, thermal spas

Pools of water in the town of Furnas boiled at up to 150ᵒC.

Fumaroles, geysers, boiling mud pits, thermal spas, and lunch cooked by volcano highlighted the day we spent in the town of Furnas, within the Furnas volcano’s caldera.

“This is the safest place on the island,” said Ruben, a guide we kept running into while exploring the boiling water pits. He generously included us in his explanations, even though we hadn’t hired him. “We call this the lungs of the island. Otherwise, ‘boom!’”

Volcanoes that constantly emit steam and gases are less likely to erupt, he explained. At one pit, we stood mesmerized by the loudly boiling, roiling water that Ruben said was 150ᵒC.

“You can go swimming… once!” he joked.

Down the street, he stopped at a water pipe disgorging 80-to-90ᵒC water into a fountain to show us a “magic trick.” He lit a cigarette, inhaled, and blew the smoke over the hot water, resulting in instant billows of puffy steam. The nicotine and other chemicals mixed with the water’s sulphur to produce the steam.

We smelled a mix of mineral odours but strangely, the town did not reek of sulphur, as we’ve experienced in other volcanic places we’ve visited, such as Rotorua, New Zealand.

At Furnas Lake, boardwalks led visitors amongst the boiling mud pits and fumaroles venting hot steam and volcanic gas.

Furnas has two areas where you can see volcanic action: one right in town, where we met Ruben; the other next to Furnas Lake, a few kilometres from town.

At Furnas Lake, we followed boardwalks in and around the boiling mud pits, marvelling at the greyish mud bubbling, burping and emitting huge swathes of steam. Signs warned us “Don’t step on the boil zone.” We obeyed.

Several feral cats, however, sat and slept on the warm earth near some small steam vents. Cats! They always seek out warmth! Perhaps we’re part cat, but we did the same. Along the lake edge, steam escaped from some small vents. We tried to hold our hands near but had to yank them away. The lake water near the shore was distinctly warm too, with bubbles in some spots. Such a weird sensation for Canadians used to cold lakes.

We watched our Cozidos das Furnas lunch being cooked at Furnas Lake.

Another volcanic feature at Furnas Lake is seeing your lunch cooked!

Several carefully constructed dirt mounds had signs atop with the names of restaurants. We found the sign for Tony’s Restaurant, where we had reservations for a lunch of Cozidos das Furnas – a stew that’s cooked by the volcano.

Restaurants place chunks of chicken, beef, pork, cabbage, carrots, chorizo, blood sausage, potatoes, kale and more into large heavy pots. The pots are placed into holes dug in the hot ground, where the stew cooks for six hours or so, taking advantage of the 100ᵒC heat.

Just before lunch, men arrived to scrape the soil away, lift the lids, and use long metal hooks to lift the pots and carry them to vans waiting to deliver the food to the restaurants. When we peered into some of the empty holes, we could see water at a rolling boil.

Back in town, we enjoyed our lunch at Tony’s. The servings were huge and delicious, served with rice and a sauce. We had enough left over for two more meals.

Ahhhhh. Thermal spas are wonderful!

We rounded out our Furnas day by soaking in the volcano-heated thermal pools at the Poca da Dona Beija hot springs. Orangey-red iron settles out of the water onto stone ledges and pool bottoms. Hot spring staff warn you it can discolour bathing suits, but even my white suit didn’t suffer any ill effects.

We tried each of the thermal pools, set in pretty gardens along a central stream. The pools varied in depth, some with waterfalls, but all filled with mineral-rich waters of 39ᵒC that soothed our aches and pains.

On our way to and from Furnas, we passed by a geothermal power plant – another testimony to the island’s subterranean power source.

Black beaches and sea stacks

Mosteiros’s black sand beach, four sea stacks, and tide pools are all remnants of volcanic eruptions.

We left footprints on several sparkly black sand beaches, including in the town of Mosteiros, so named because one of the four sea stacks offshore looks like a monastery (‘mosteiros’ means ‘monasteries’ in Portuguese). The four rocky stacks are leftovers from a volcanic eruption, worn down by waves over centuries.

We investigated Mosteiro’s natural tide pools, formed from porous volcanic rock that, in some places, showed folds from the oozing lava. But the waves were so high that day, breaking right over the ladder on the pool edge, that we declined to go swimming.

Rodrigo had told us about two places on São Miguel (Ponta da Ferraria and Ribeira Quente) that have thermal tide pools, where underwater thermal springs mix with ocean water to create spa-like warm salty waters for soaking. However, they’re best enjoyed when the tide is low and our timing wasn’t right.  

Things made from volcanic rock

Volcanic rock of several types is used all over São Miguel, illustrating the island’s origins.

Several types of volcanic rock – including porous pumice and smooth basalt – are used all over São Miguel: as the black trim on homes, churches, museums, government buildings, bell towers and Ponta Delgada’s city gates. Fountains and picnic tables, crosses and convents, even the fireplace in our rented apartment were built with the ubiquitous stone.

Cows turned grass into milk in pastures surrounded by tall black stone walls that serve as windbreaks. We saw more of the thin walls on the west end than in the east.

Even the calçadas – the small white and black cobbles used for Portuguese sidewalks and plazas all over the country – are different on São Miguel. In mainland Portugal, the calçadas are mainly white with black designs. On São Miguel, they’re mainly black with white designs. We even saw a pineapple design – symbolic of the island’s fertility.

Fertile volcanic soil

São Miguel is the only place in Europe where tea is grown industrially.

I imagined that São Miguel’s fertility is the volcanoes’ way of apologizing for any death and destruction caused in the past. Lava and ash break down into incredibly rich soil, full of key nutrients for plant growth, including iron, calcium, magnesium, sodium, potassium, phosphorous, sulfur, and silicon.

The first evidence of that fertility we saw was lush green pastureland, outlined by rows of hydrangeas that line just about every road. This Asian native is an invasive species in the Azores, but it’s certainly a beautiful one. At the end of October, the blooms were coming to an end, but we still saw the puffy flowerheads everywhere. When the soil is acidic, they bloom in blue; in less-acidic soil, they bloom in pink, purple or white. But we saw countless places where they bloomed in all colours, indicating a mix of soils even in one small garden.

Tea is a surprising product of the island’s fertility. Two tea plantations – Gorreana (established in 1883) and Porto Formoso – are the only places in Europe where tea is grown industrially. The aroma of dried tea leaves greeted us when we toured both, learning the various steps involved from picking, through steaming, rolling, oxidization, drying, blending, and then to packaging.

Only the top three leaves are picked from the flat-topped hedges. I hadn’t known that orange pekoe tea comes from the most tender top leaf, while pekoe comes from the second leaf – I’d thought the two teas were the same. The third leaf produces broken-leaf tea – the least expensive and one I’d never heard of.

At Gorreana, we hiked amongst the tea hedges to a waterfall, which supplies a water tank used to create electricity for the plantation. Along the way, we passed hydrangeas, ferns, tree ferns (reminding us of New Zealand), kahil ginger, plane trees and countless mosses.

Pineapples, milk and cheese, trees from around the world, and even grapes enjoy the rich volcanic soil on São Miguel.

The warm Atlantic Gulf stream comes close to the Azores, giving the islands a mild climate. That, combined with rich volcanic soil, leads to tropical fruit.

In the mid-1800s, oranges were São Miguel’s main export. But a devastating fungus, combined with competing markets in Italy and Spain, sounded the death knell for oranges. Many wealthy orange growers tore out their trees, replacing them with tea, botanical gardens, and pineapples.

Pineapples like the volcanic soil but not the temperatures, so they’re grown in greenhouses. At the Augusto Arruda Pineapple Plantation we took a self-guided tour through greenhouses that showed the two-year, seven-stage process of growing pineapples. (Stage 4 involves filling the greenhouse with smoke to force the plants to flower at the same time.)

Augusto Arruda built the plantation in 1919 in a former orange grove. Now, the fifth generation of his descendants runs it. In the shop, we sampled pineapple liqueur and bought pineapple jam. Bill even surprised me with a necklace with a tiny pineapple charm.

Later, at the Mercado da Graça [farmer’s market], I bought a tiny ripe pineapple that tasted lusciously sweet. Other pineapple treats we sampled in various places included smoothies, cake, and even tea (although the pineapple wasn’t terribly strong in the tea).

At the José do Canto Botanical Garden, we kept our eyes peeled, unsuccessfully, for the small Azores noctule – a bat that hunts insects during the day and is the island’s only native mammal. We didn’t see any bats, but we did enjoy wandering amongst notable tree specimens from around the world. The most spectacular was the Moreton Bay Fig from Australia, with spreading vertical wall-like roots as tall as us.

Black-and-white cows munched the emerald-green grass even on the steep sides of pointy-topped hills – old volcanic cones. The island’s dairy industry produces milk and cheese that supply mainland Portugal. We sampled and bought several varieties in a cheese shop in Ponta Delgada’s farmers’ market.

We hadn’t realized there’s a small wine industry on São Miguel. After we toured the Farol do Arnel lighthouse, climbing up into the lantern room to see the enormous lens, the lighthouse keeper invited us to share a glass of wine with him. We began with a red from mainland Portugal, but then he ducked inside the lighthouse (where he lives with his family) and returned with a red Terras de Lava that is “born in lava soils, filled with mineral nutrients, expresses the ‘volcanic terroir’ in a genuine way” according to the blurb on the bottle. I later discovered it’s actually from the Azorean island of Pico, but there is a winery on São Miguel too. Vines are protected from wind by the tall walls built of basalt.

The incredibly steep road zigzagging down to the Farol do Arnel lighthouse kept on going down to a fishermen’s pier, where frothy waves pounded against the lava-boulder beach.

Displays and information boards in various places, plus museums and a walking tour offered us the facts and explanations about São Miguel’s fiery past. We even saw a two-foot-long missile-shaped volcanic bomb, expelled from a volcano, in the Carlos Machado natural history museum in Ponta Delgada. But seeing the evidence in the landscapes before our eyes led to a better understanding of how volcanoes leave a lasting impact.

We explored São Miguel in October-November 2023. Find out where we are right now by visiting our ‘Where’s Kathryn?’ page.