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Mt etna - erutions and response
 

Mt etna - erutions and response

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    Mt etna - erutions and response Mt etna - erutions and response Presentation Transcript

    • Mt Etna
    • The location of Mt Etna – where exactly is Mt Etna? Mt Etna is Europe’s highest and most active volcano. It is located on the east coast of Sicily, towering 3340m over the city of Catania.
    • What plates are involved? • The African (oceanic) plate is subducted under the Eurasian (continental) plate. As well as producing Mt Etna, Vesuvius was also formed, but it is part of a different volcanic arc.
    • What is located around Mt Etna? • More than 25% of Sicily's population lives on Etna's slopes. It is the main source of income for the island both from: • Agriculture (due to its rich volcanic soil) The lowest parts of the mountain floor is fertile and rich in vineyards, olive groves, citrus plantations, and orchards • And tourism – Home to the Piano Provenzano ski resort (this was destroyed in the 2002 eruption) • There are towns and villages surrounding the mountain, including Catania. In the past, the Italian authorities have used explosives, concrete dams, and ditches to divert lava flows away from these settlements.
    • What type of volcano is it? The history of the creation of Mt Etna – what has caused the volcano to be created? • Mt Etna is a composite (stratovolcano), made up of layers of ash and solidified lava. • The volcano has more than one active chamber, this has resulted in many subsidiary cones (craters on the side of the volcano). • It has been growing for about 500,000 years and eruptions began in 2001. Eruption styles include: violent explosions and huge lava flows. • The volcanic summit was about 52 metres higher than it was in the early 21st century.
    • What are the physical characteristics of Mt Etna? South East Crater Dyke – exposed due to erosion Horseshoe shaped depression – provides a channel for lava
    • Mt Etna-1971 Katie and Julia
    • Build up to eruption • “Until the present eruption began, Mount Etna had been in a state of more or less continuous activity from a small cone connected to the central cone by a low pass. About one month before the eruption began, the activity in this small cone, the north-east crater, started to die down; and two weeks before the eruption a local guide noticed that a small patch of snow at the southern foot of the central cone was beginning to melt”
    • • “On 5th April the eruption began, and two fissures, 80-100m long opened where the snow had been melting. The area below the main cone of Etna is rather flat, having been formed over the past 300 years by lavas in-filling a depression caused by the collapse of the central cone after the particularly violent eruption of 1696.”
    • • Gas soon built up cinder cones by throwing out molten rock. By the 16th April, the eruption showed signs of slowing down. It built up again 22nd of April and the formation of the South Eastern crater began. • http://www.youtube.com/watch?v=OpbHn9CQxt4
    • Formation of South-east crater • The Southeast Crater seen from the air immediately after its formation in spring 1971 (top) and in May 2008 (bottom). • Since its formation in 1971, the crater has grown 300 m above its original size of 2990m.
    • Effects • Mount Etna erupts and the lava destroyed ski slopes, cable car station and observatories.
    • Summary • The latest addition to Etna’s summit crater family is the Southeast Crater, which formed during a flank eruption in May 1971 at the south-eastern base of the central summit cone as a sort of pressure valve – while lava was emitted a few kilometres further downslope to the northeast, it emitted vapour-rich ash clouds for a couple of weeks.
    • 1991 – 1993 eruption
    • Nature of the event • > The eruption started in 1991 on 14th December and lasted for 473 days which is the most volumous eruption from Etna in over 300 years (250 million m3) • > The lava flowed down the south east flank of the volcano into the Valle del Bove • > The eruption had a low rate of lava emitted which posed very little threat to human life
    • Impacts- Social There were No deaths as a result of the eruption. The lava destroyed the springs which provided the water supply to the town of Zafferana with a population of 8,000 people. Several people who lost homes and farm land in the Val del Bove blamed the government for not acting soon enough. In interviews made during the late 1990’s with people from the Zafferana area, when asked about their fear of a future eruption, many of them expressed that they had no fear because ‘when there will be a lava flow, it will be diverted anyway.’
    • Impacts – Economic and Environmental The total cost of the management and responses as well as insurance claims for damage to property ran into millions of Lira Vineyards and Chestnut orchards were destroyed
    • Immediate/short term responses During 1992 the Italian authorities built an earth barrier over 400 metres long and 20 metres high in order to stop the lava reaching the town of Zafferana – this contained the lava for about a month before overflowing. 3 smaller embankments were built after this. The US marines then became involved in ‘Operation volcano buster’ in which they used explosives to blast a hole in the lava tube and then used helicopters to drop concrete blocks in the main lava flow in order to slow down the lava. Finally, a diversion channel was dug and explosives were used to divert the lava onto an adjacent flank of the volcano. The overall outcome of these interventions resulted I the lava flow stopping 850 metres from Zafferana but some geologists argued that the eruption was ending anyway.
    • Long term responses The Institute of volcanology in Sicily (INGV) has continued to improve methods of monitoring since the 1992 eruption – b measuring radon gas to detect lava movements within the volcano, using GPS to examine changes to the slope angle of the volcano and using highly sensitive seismometers to measure minute tremors which might indicate lava being forced into the volcano. The responses involved many different organisations including the police, fire brigade, the civil defence department, the local council, geologists, volcanologists, the Italian army, Italian Red Cross and the US army.
    • 2002-2003 Eruption
    • • http://www.youtube.com/watch?v=Rzln5Y-aUrQ
    • Effects of this eruption • The eruption completely destroyed the tourist station at Piano Provenzana and part of the tourist station at Rifugio Sapieza, located on the south side of the volcano. It took the lava 2 weeks to reach the tourist centre of Rifugio Sapienza. • Damns of soil and volcanic rock were put up to protect the tourist base at Rifugio Sapienza and helped to divert the flow. • There were losses in agriculture and tourism because many people stayed away due to safety concerns, the Italian government pledged immediate financial assistance of more than $8m and tax breaks for the villagers.
    • Star Wars! • Footage from the eruptions was recorded by • Lucasfilm and integrated into the landscape of the • planet Mustafar in the 2005 film Star Wars Episode • III: Revenge of the Sith.
    • 2007-2008 – Mount Etna
    • The eruptions 2008 An eruption on the morning of 13 May 2008, immediately to the east of Etna's summit craters was accompanied by more than 200 earthquakes and significant ground deformation in the summit area. The eruption continued at a slowly for 417 days, until 6 July 2009, making this the longest flank eruption of Etna since the 1991–1993 eruption that lasted 473 days. Lava flows streched 6.5 km during the first few days of this eruption but thereafter stagnated at much minor distances from the vents; during the last months of the eruption lava rarely advanced more than 1 km downslope. 2007 On 4 September 2007 an episode of lava fountaining occurred from the new vent on the east side of the Crater This produced a plume of ash which fell over the east flank of the volcano. A lava flow travelled about 4.5 km (2.8 mi) into the uninhabited Valle del Bove. This eruption was visible far into the plains of Sicily, ending the following morning between the hours of 5 to 7 am local time.
    • Economic -Orange groves and vine yards were wiped out in Zafferanna – affecting the local businesses. -Roads became covered in ash so it was hard to access anywhere that had been affected -Ski areas were ruined – this had a strong impact on the masses of tourism that Mt Etna brings to Sicily. -Animals were killed and farm areas were destroyed and covered in ash. -The airport was forced to close due to ash on the runway – again affecting tourism.
    • Environmental On 4 September 2007 a spectacular episode of lava fountaining occurred from the new vent on the east side of the Southeast Crater, also producing a plume of ash and scoriae which fell over the east flank of the volcano. A lava flow travelled about 4.5 km (2.8 mi) into the uninhabited Valle del Bove. This eruption was visible far into the plains of Sicily, ending the following morning between the hours of 5 to 7 am local time. Catania-Fontanarossa Airport shut down operations during the night for safety precautions. An eruption on the morning of 13 May 2008, immediately to the east of Etna's summit craters was accompanied by a swarm of more than 200 earthquakes and significant ground deformation in the summit area. The eruption continued at a slowly diminishing rate for 417 days, until 6 July 2009, making this the longest flank eruption of Etna since the 1991–1993 eruption that lasted 473 days. Lava flows advanced 6.5 km during the first few days of this eruption but thereafter stagnated at much minor distances from the vents; during the last months of the eruption lava rarely advanced more than 1 km downslope. Farm land is ruined by the volcanic eruption, thus reducing the biodiversity of plants and animals occupying the natural landscape surround Mount Etna.
    • 2009-Present Mt Etna
    • 2008-2009 • An eruption on the morning of 13th May 2008 on the east of etnas summit craters, was accompanied by more than 200 earthquakes and significant deformation of the ground in the summit area. • The eruption continued at a slowly diminishing rate for 417 days which carried on to 6th July 2009. This was the longest eruption of Etna since 19911993 eruption that lasted 473 days.
    • 2010 • An ash eruption occurred at the summit of Mt Etna on 8th April 2010, the eruption occurred at the lower east flank of the south-east crater. Following the eruption there was a series of earthquakes at the Pernicana fault on the 2nd April. This was the first time in six years that earthquakes occurred in this location on Mt Etna. • The largest earthquake was magnitude 4.2. ground cracking occurred and Mareneve road, which links the town of Linguaglossa to the tourist area of Piano Provenzana, was fractured in two locations. • The earthquake was focused at a depth of 1km and surface fractures occurred over a distance of 1km.
    • 2011 • On the evening of 11th January 2011 an increase in volcanic tremor was recorded at Mt Etna volcano. Seismic activity reached a peak at 07:00 hr on 12th January when the source moved from north of NE crater to the SE crater. • About 21:00 hr, lava overflowed the eastern rim of SE crater, and fed a flow that moved toward the western wall of the Valle del Bove. • Lava fountains occurred at SE crater. • The eruption consisted of a sustained lava fountain, lava flow, and an ash column reaching several kilometres high. The lava fountain lasted 42 minutes from 22:48-23:30 hr on 12th January and reached a height of 300-500 m. The lava fountain became pulsating after this time and reached a height of 100-200 m until 0:55 hr on the morning of 13th January. Ash fall was reported on the south flank of Mt Etna. • A lava flow descended the western slope of the Valle del Bove in three branches and reached the base after midnight. The longest flow surrounded the northern side of Monte Centenari, 4.2 km from the vent. On the 13th January ash emissions were caused by a partial collapse within the cone and eruptive activity at Mt Etna's SE crater. • Effects included the airport had to be closed
    • 2013 • Eruptions occurred at 3 craters at Mt Etna volcano in February 2013. • Five paroxysms (sudden outburst of activity) at new southeast crater over past week. On 27th February Strombolian (low level eruption) eruptions and small lava fountains were observed at Bocca Nuova crater. • Magmatic activity has occurred at Voragine for the first time since 1999. Renewed eruptions on October 26 2013 occurred at new southeast crater and northeast crater. • http://www.youtube.com/watch?v=E2Wz nb_e45o
    • Responses to the Eruptions of Mt Etna By paula and abi
    • 1971 • The government planned a disaster response in advance of the eruption in order to save the lives of people living near the danger zone. Aerial photographs were taken to map geographical features of the Volcano eruption. The government was looking for flank eruptions, rather than a summit eruption, which are known to cause considerably more damage. The rumblings and sounds were closely monitored to help predict the eruption. Ground temperature measurements were made. A rise in temperature could indicate a location of a build-up of magma below the central crater. • There were orderly evacuations where necessary. • Mobile aid was available and good there was good communication.
    • 1991-93 • INGV (the institute of the volcanology) in Sicily had continued to improve methods and monitoring since 1992 eruption. They measured raidon gas to detect lava movements. • They used a GPS to examine changes in the slow angle in the volcano • They used seismometers to measure minute tremors which might indicate lava being forced into the volcano • Organisations such as the police and fire brigade and Red Cross came to help and assist the situation
    • 1991-1993 During 1992 the Italian authorities built a barrier over 400 meters long and 20m high to stop the lava reaching zafferana. This contains the lava for about a month before overflowing. 3 smaller embankments were built. The US marines used explosives to blast a hole in the lava tube and then used helicopters to drop concrete blocks into the main lava flow to slow down the lava. And divert it. A diversion channel was also dug to divert the lava The lava flow stopped by 850 meters from Zafferana
    • 2001 eruption Immediate Long Term Decision to shut airport was on 29th July Rebuilding damaged buildings Panic Scientists improve monitoring of volcano People moved out of the area More planning of emergency services and evacuation plan Villagers in Nicolosi prayed to reduce impact of eruption Use tourism to generate money and income from the area US Army helicopters dropped 2 tonne concrete blocks to stop lava flow Italian government gave tax breaks to help villagers get through the crisis Earth dams were built to redirect lava flow 500kg mines exploded to divert lava Italian government gave £5.6 million of aid
    • 2002 • People were evacuated from the dangerous areas surrounding the volcano • The government declared a state of emergency on the eastern side of Sicily • A ship equipped with medical equipment near Catania • Additionally, emergency workers dug channels into the Earth in an attempt to divert the northern flow away from the town of Liguaglossa. • Schools in the surrounding towns had to be shut down as a safety precaution. • Civil protection officials in Catania surveyed the volcano from a helicopter; however the airport in Catania had to be closed for 4 days due to ash on the runways and smoke in the air.