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Showing posts with label Lahar. Show all posts
Showing posts with label Lahar. Show all posts

Thursday, 30 May 2013

Fact File; Popocatapetl

Well... it's at it again... so... seeing as I haven't done a fact file on this volcano yet... and now the fact is that it is erupting again makes me think that its about time that I do one.. so... back to my favorite topics... Volcanoes! :)






Fact File; Popocatepetl


 Location;   Popocatepetl is 70 km (43 mi) southeast of Mexico City,
Magma Type- Predominantly Andesitic, but it has also erupted large volumes of Dacite.                                                     Magma produced in the current cycle of activity tends to be a mixture of the two.
Typical eruption style: Dominantly explosive, construction of lava domes. Plinian eruptions at intervals of several centuries or few thousands of years, vulcanian and strombolian activity in intermittent phases.

General Background;  Popocatépetl, whose name is the Aztec word for smoking mountain, towers to 5426 m 70 km SE of Mexico City to form North America's 2nd-highest volcano. The glacier-clad stratovolcano contains a steep-walled, 250-450 m deep crater. The generally symmetrical volcano is modified by the sharp-peaked Ventorrillo on the NW, a remnant of an earlier volcano.
At least three previous major cones were destroyed by gravitational failure during the Pleistocene, producing massive debris-avalanche deposits covering broad areas south of the volcano. The modern volcano was constructed to the south of the late-Pleistocene to Holocene El Fraile cone. Three major plinian eruptions, the most recent of which took place about 800 AD, have occurred from Popocatépetl since the mid Holocene, accompanied by pyroclastic flows and voluminous lahars that swept basins below the volcano. Frequent historical eruptions, first recorded in Aztec codices, have occurred since pre-Columbian time.









This 2003 photo from the International Space Station shows a pair of volcanoes in Mexico. As part of the “Ring of Fire” stretching around the Pacific, Mexico hosts several of the world’s most continually active volcanoes, including the massive Popocatepetl (Aztec for "Smoking Mountain") at left. The neighbouring volcano is Iztaccíhuatl (the "Woman in White"). The faint plume emanating from Popocatepetl’s summit crater shows the ever-present hazard the volcano represents to the 25 million people living in the region, including the nearby city of Amecameca, as well as the metropolitan centres of Mexico City to the northwest and Puebla to the east. Credit: NASA

Tuesday, 10 July 2012

Nevado del Ruiz... Its Back

Volcano Name- Nevado del Ruiz
Volcano Type- strata volcano

location- colombia

  • The Colombian volcano Nevado del Ruiz is an active  stratovolcano with a history of generating deadly volcanic mudflows lahars- from relatively small-volume eruptions.
  • In 1595, a lahar swept down the valleys of the River Guali and the River Lagunillas, killing 636 people.
  •  In 1845, an immense lahar flooded the upper valley of the River Lagunillas, killing over 1000 people.
  • It continued for 70 kilometers downstream before spreading across a plain in the lower valley floor.
  • The young village of Armero was built directly on top of the 1845 mudflow deposit.
  •  Over the ensuing years, Armero grew into a vibrant town with over 27,000 residents.
  • On November 13, 1985, history repeated itself for the third time in 400 years, with another eruption and another deadly lahar racing down the River Lagunillas.
  •  This time, over 23,000 people were killed, including most of the residents of Armero. With proper planning, this tragedy could have been averted.
  • over the last week the volcano has rumbeld back into life as can be seen on the web-Cams on the BBC page : http://www.bbc.co.uk/programmes/p00tmqd6/features/webcams 
  • what could this mean for the people who live below the volcano?.. it remains to be seen... however hopefully due to the increase in knowlage of the volcano and increased monitoring the effects will be mitigated and the damages decreased!