
Tv: Här störtar glödande lavabomb fram på La Palma
Forskare har fångat på film när en vulkanisk bomb, eller så kallad lavabomb, störtar ner längs bergssidorna från vulkanen Cumbre Vieja på La Palma.
Harri Geiger, forskare inom geokemi på Albert-Ludwigs universitet i Tyskland, är på plats för att undersöka utbrottet som har pågått sedan 19 september. Han och kollegorna samlade in prover i vulkanzonen den 28 oktober när den vildsint glödande bumlingen plötsligt dök upp, rapporterar Gizmondo.
I ett mejl skriver Geiger att han uppskattar lavabombens storlek till omkring en meter i diameter. Den ska ha vägt omkring ett halvt ton.
bakgrund
Vulkanisk bomb
Wikipedia (en)
A volcanic bomb or lava bomb is a mass of molten rock (tephra) larger than 64 mm (2.5 inches) in diameter, formed when a volcano ejects viscous fragments of lava during an eruption. They cool into solid fragments before they reach the ground. Because volcanic bombs cool after they leave the volcano, they are extrusive igneous rocks. Volcanic bombs can be thrown many kilometres from an erupting vent, and often acquire aerodynamic shapes during their flight. Bombs can be extremely large; the 1935 eruption of Mount Asama in Japan expelled bombs measuring 5–6 m (16-20 ft) in diameter up to 600 m (2,000 ft) from the vent. Volcanic bombs are a significant volcanic hazard, and can cause severe injuries and death to people in an eruption zone. One such incident occurred at Galeras volcano in Colombia in 1993; six people near the summit were killed and several seriously injured by lava bombs when the volcano erupted unexpectedly. On July 16, 2018, 23 people were injured on a tour boat near the Kilauea volcano as a result of a basketball-sized lava bomb from the 2018 lower Puna eruption.Volcanic bombs are known to occasionally explode from internal gas pressure as they cool, but in most cases, most of the damage they cause is from impact, or subsequent fire damage. Bomb explosions are most often observed in "bread-crust" type bombs.
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