MT VESUVIUS, ITALY - AN INTRODUCTION.

The next Decade Volcano we are going to look at is Mt Vesuvius, situated east of Naples, Italy, and is 4200 feet high (1281m).

Vesuvius is a stratovolcano at the convergent boundary where the African plate is being subducted under the Eurasian Plate. Its lava is mainly made up of viscous andesite. Vesuvius is still regarded as an active volcano although recently its activity is limited to producing little more than steam from its vents at the bottom of the crater.

View of Mt Vesuvius (from http://www.windows.ucar.edu/earth/images/Mt_Vesuvius.jpg)

Vesuvius is best known for its eruption in 79AD that was responsible for the destruction of Roman cities Pompeii and Herculaneum.

The eruption of Vesuvius in BBC/Discovery Channel's co-production Pompeii.

Besides the 79AD eruption, Vesuvius have also erupted many times before and after, which vary in severity, but all were characterized by explosive outbursts called Plinian eruptions. There has been no eruption since 1944, and none of the post-79 eruptions were as large or destructive as it.

Eruption in 1944- from http://www.nsa.naples.navy.mil/disasterprep/art/vesuviusbandw.jpg

Vesuvius is a dangerous and deadly volcano. Mudflows and lava flows from the eruption in 1631 killed 3,500 people. About 3,360 people died in the 79 A.D. eruption from ash flows and falls. Studies of past eruptions and their deposits continue. These studies help volcanologists understand the hazards associated with future eruptions. The population density in some areas of high risk is 20,000 to 30,000 per square km. About 3 million people could be seriously affected by future eruptions. In the first 15 minutes of a medium- to large-scale eruption an area with a 4 mile (7 km) radius of the volcano could be destroyed (Dobran and others, 1994). About 1 million people live and work in this area.


Next post - Formation of Mt Vesuvius!

**Information taken from http://volcano.und.edu/vwdocs/volc_images/img_vesuvius.html and wikipedia.org

Lari!!! Cepat Lari!!!

Translation: Run!!! Faster Run!!!

After a month or so of warnings and threats, spewing lava and black ash, Indonesian authorities finally raised the alert level to the highest because there have been constant lava flows that have caused hot gases.

With the raised alert levels come the compulsory evacuation of thousands living on the slopes of the volcano. prior to this evacuation has only been voluntary, and many were reluctant to leave crops, property and livestock untended. for the villagers, who were mostly farmers living off merapi's fertile soil, these were their lifelihood.

Despite the fact that 27, 000 locals in 3 villages could have been affected by the eruption, none were killed. large gas and ash clouds killed 60 in the 1994 eruption and 1,300 in 1930. perhaps this time around the death toll was kept under wraps by an affective and efficient mix of prediction and evacuation.

Prediction:
The Directorate of Volcanology and Geological hazard Mitigation runs the Merapi Volcano Observatory, hich is responsible for overseeing Merapi's activities and providing the authorities with warnings, and professional advise to mitigation. Using the usual set of predition tools, MVO would issue warnings based on a four level alert system.

Alert System:
1. Aktif Normal (Normal Activity)
2. Waspada Merapi (Attention)
3. Siaga Merapi (Standby)
4. Awas Merapi (Evacuation)
A series of sirens set up in Merapi's surrounding areas will be set off when the alert level is raised to "Awas" and the local government is responsible for the people's evacuation.

Hazard Map:






















Merapi Hazard Map (Picture taken from: http://www.vsi.esdm.go.id/mvo/fig28.JPG )

Long before the 2006 eruption, the authorities came up with this Hazard Map picking out the areas that are most at risk and even showing what they are most in danger of. Such maps aim to give the people and the local government an understanding of their neighbour (Merapi lah!), such that they would know what they can expect and to work around this. For example the local government would know not the place any important infrastructure in the high hazard zones and would also be looking into areas in the low/ no hazard areas for possible evacuation centres.



Evacuation:
Of course, without evacuation, many MANY Indonesians would have been dead by now, even with the blaring sirens, fancy tools and jellyfish-maps. this time around, the authorities did pretty well in terms of organising evacuation camps and preparing evacuation trucks to bring the villages in masses to the evacaution camps. the only downfall here, was that merapi's eruption seemed to last forever, and people started to get more and more worried about their property and lifestock and had wanted to go home. some of those who had voluntarily left for the evacuation centres did return home but had to return to the evacuation centres when evacuation was made compulsory.















Villagers leaving for evacuation centres on lorries.
(Picture Taken from: http://mdn.mainichi-msn.co.jp/photospecials/graph/0515volcano/33.html)














A couple evacuating on their motorbike as Merapi shoots out her largest ash cloud yet.
(Picture taken from: http://www.guardian.co.uk/Guardian/gallery/image/0,,-1040329481742,00.html )

A farmer trying to salvage crops that have been buried and burned under tons of ash. (Picture taken from: http://www.guardian.co.uk/Guardian/gallery/image/0,,-1040329481742,00.html)

From this we see, that with the 2006 eruption, the local government's evacuation efforts together with well honned prediction methods helped saved thousands of lives, showing the importance of proper hazard management.

NB: on the 27th May, 2006, a 6.2 magnitude earthquake struck in yogyarkarta that killed over 5000 people. the jury is still out about whether the merapi eruption triggered the quake or if the eruption was simply a precursor to the quake.

Merapi Blows Her Top

After weeks of taunting... Merapi finally erupts on the 17th May with the largest cloud of hot gases yet. Typical of it's stratvolaconoe character, Merapi erupted in the highly eruptive Plinian fashion throwing up ash clouds kilometres high. Days before this eruption, Merapi had sent debris more than 2 miles down her slope along with smaller ash clouds. The top of Merapi was obscured by thick grey and white clouds, which trailed down the volcano’s slopes.














Merapi sending the largest ash cloud so far as she erupts. (taken from http://a.abcnews.com/images/International/EKW11205150205_sp.jpeg)

scenes of the eruption

There is caution however, that Merapi's eruption process could be gradual rather than a sudden burst, and that the massive eruption might had yet to come.

• The pyroclastic flows of ash, gas and debris are generated at the volcano's summit which increases in size when the hot lava dome grows larger.
• Once the dome collapses, there will be landslides and avalanches down the sides of the volcano, destroying everything in its path.
• They can spread over the wide area, being easily picked up by the wind.
• When this happens, more hot air and gas are released and its fluidity is increased rapidly.
• With its acceleration and unpredictability of predicting where it might go (unlike lava flows), it is therefore much harder to plan effective evacuation routes.
• Further dangers include pyroclastic flows burning people alive, destroying infrastructure, killing crops and livestock and its ash pose a safety threat to the poorly constructed houses (possible buckling and collaspe) typical of the area around Mt Merapi.

In the next post, we'll look into the prediction and mitigation of Merapi's 2006 hissy fit (eruption).