Scientists monitoring the Holuhraun eruption area are expecting to witness, for the first time, the live formation of pseudocraters. Pseudocraters, also knwon as Rootless cones, are formed by steam explosions when glowing hot lava flows over a wet surface, which is exactly what's happening now in Iceland's central highlands (see late in this Stöð 2 TV news segment).
The red-hot Holuhraun lava is advancing fast over the riverbed of Jökulsá á Fjöllum. The glacial river flows through many branches in the area and as the lava enters the main branch the water moves away, forming big steam clouds. This is the ideal condition for the formation of pseudocraters, which resembles a true volcanic crater, but differs in that it is not an actual vent from which lava has erupted. The explosive gases break through the lava surface in a manner similar to a phreatic eruption, and the tephra builds up crater-like forms, which can appear very similar to real volcanic craters.
We have many well known pseudocraters in Iceland. The most famous ones are in the lake Mývatn region in North Iceland, not far from the ongoing Holuhraun eruption. Another example is the Rauðhólar craters on the outskirts of Reykjavík.
Scientists monitoring the Holuhraun eruption area are expecting to witness, for the first time, the live formation of pseudocraters. Pseudocraters, also knwon as Rootless cones, are formed by steam explosions when glowing hot lava flows over a wet surface, which is exactly what's happening now in Iceland's central highlands (see late in this Stöð 2 TV news segment).
The red-hot Holuhraun lava is advancing fast over the riverbed of Jökulsá á Fjöllum. The glacial river flows through many branches in the area and as the lava enters the main branch the water moves away, forming big steam clouds. This is the ideal condition for the formation of pseudocraters, which resembles a true volcanic crater, but differs in that it is not an actual vent from which lava has erupted. The explosive gases break through the lava surface in a manner similar to a phreatic eruption, and the tephra builds up crater-like forms, which can appear very similar to real volcanic craters.
We have many well known pseudocraters in Iceland. The most famous ones are in the lake Mývatn region in North Iceland, not far from the ongoing Holuhraun eruption. Another example is the Rauðhólar craters on the outskirts of Reykjavík.
