On August 24 79 AD Mount Vesuvius erupted and ultimately destroyed Pompeii. With a red alert issued on Saturday (later back downgraded to orange), when and how will Iceland's Bardarbunga volcano erupt? On Sunday there were earthquakes of magnitude 5.3 and 5.
History of Vesuvius Eruption
Pliny, a Roman administrator and poet, wrote of the event. Some of the warning signs were ignored. Earth tremors were not particularly alarming because they are frequent in the town of Campania. The long inactivity of the volcano naturally lulled the people of the region into a false sense of security. This was true even though they were aware of the signs of burning at the peak of the mountain. From its start on the morning of 24 August, the eruption lasted for more than 24 hours. A rain of ash and pumice fell for several hours but was not necessarily lethal. Most inhabitants thought to wait it out and did not leave the area. Around midnight, the first pyroclastic (flow that is of hot ash, pumice, rock fragments and volcanic gas, which rushes down the side of a volcano) surges started. After the initial intense heat, the subsequent waves asphyxiated and then smashed the flat upper floors and finally encased all.
Current History of Volcano at Bardarbunga
There was first and increase in seismic activity which they became more intense. In the last week, more than 3000 earthquakes have been detected with the earthquake monitoring network of the Icelandic Meteorological Office (IMO). They were at a constant depth (not closer than 3.8 km usually 5-12) and not coming to the surface. The magma intrusion extends 5 km (3 miles) beyond the edge of Dyngjujökull, an outlet glacier on the northern border of Vatnajökull, approaching a fissure swarm belonging to the volcanic system of Askja in the northeastern highlands of Iceland.
As of 10 AM on August 25, scientists from the Icelandic Met Office, Institute of Earth Sciences and representatives of the Civil Protection Department declared at their meeting:
There are no indications that the intensity of the activity declining. Currently, three scenarios are considered most likely:
- The migration of magma could stop, attended by a gradual reduction in seismic activity.
- The dike could reach the surface of the crust, starting an eruption. In this scenario, it is most likely that the eruption would be near the northern tip of the dike. This would most likely produce an effusive lava eruption with limited explosive, ash-producing activity.
- An alternate scenario would be the dike reaching the surface where a significant part, or all, of the fissure is beneath the glacier. This would most likely produce a flood in Jökulsá á Fjöllum and perhaps explosive, ash-producing activity.
Other scenarios cannot be excluded. For example, an eruption inside the Bárðarbunga caldera is possible but presently considered to be less likely.
The 6.0 earthquake at Napa Valley was just that an earthquake along a ready known fault. There are volcanoes in California (not very active) but they are at least 3 hours away from there.
Icelandic Met Office - en.vedur.is/