The Afar Triangle

In 1912, Alfred Wegener published his proposal that continents had moved. He presented various lines of evidence, of which the best remembered is the fact that the opposite shores of the Atlantic ocean fit together as pieces of a puzzle. There was much more, including the fact that earthquakes were focussed on the Pacific ring…

The Messinian Salinity Crisis: Salt of the Earth

Two pillars sit at the end of the world. To the ancients, the entrance to the Mediterranean Sea was the end of the known (civilized) world. Mythology tells us that Hercules smashed the mountains to create an opening, flanked by two pillars. We don’t quite know which mountain was the southern pillar, but the northern…

The Ljósufjöll earthquake swarm

Iceland can do surprises. Its main activity is in a limited number of volcanoes which can erupt anytime, with frequencies ranging between once per century to twice per decade. These are the usual suspects, including Grimsvotn, Bardarbunga, Askja, Katla, Hekla, Krafla. (Grimsvotn is the only one not ending in ‘a’.) The beasts can go small…

The 1607 Bristol tsunami

Some events can cast long shadows. The UK is still talking about the storm of 1987 (‘the worst night since the Blitz’), the winter of 1963, the storm floods of 1953, the London smog of 1952, the Great Storm of 26 November 1703. Other countries have their own stories. But one event in particular still…

The Pahala swarm

Hawai’i is a marvellous place for a seismograph. There is something to see every day. HVO has been at the forefront of this, and had as many as 7 seismometers already in the 1940’s.Their network has been expanding ever since. The instruments are located mostly in the main areas of activity (i.e. Kilauea and its…

Flores and the Lewotobi eruption

Update 8 Nov 2024 As commented below, NASA has produced a new image and image slider showing the ash cloud from the eruption: https://earthobservatory.nasa.gov/images/153549/mount-lewotobi-laki-laki-spews-ash The lava flow running east is the one produced in January-March. The blacker ash covers around 20km>sup>2 in this image. That suggests a volume of 0.01 to 0.001 km3: no more…

Barren Island, India

A trivia question: can you name the largest country without an active volcano? Here ‘active’ includes ‘dormant’: it is about volcanoes that have access to live magma and could in principle erupt, even if at the moment it decides not to. Monogenetic volcanic fields, if active, also count. Answers through the comment box – there…

Santorini: Beauty – and the Beast

1 million people visit Vesuvius each year. It is a big number which involves a lot of people struggling up the steep and dusty path to the rim. Rather more people visit the more accessible archaeological monument to Vesuvius that is Pompeii: counting those as well brings the total to 2.5 million. It makes it…

The Aral Sea

Here is the famous Steppe, the dry grass-land, the never-ending plain stretching across Eurasia from China to Hungary. Rainfall is too limited for trees to grow. The climate is harsh, with hot summers and cold winters. But this hostile land can make a good living for those who know where to find water. It was…

Fluorine

Jon Steingrimmson was deeply worried. The eruption had been going on for three weeks already. Lava coming down from the hills, flowing down the river valleys and covering the farm land. But it wasn’t the lava that was doing most of the damage (at least not yet – worse was to come). It was what…