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).

Pre-eruption SIGNS!!

A famer having a cigarette break alongside the smoking Mt Merapi.


Mt. Merapi angrily spews large amount of gas which are rich in sulphur (as seen from the happily-bright yellow color)

(pictures taken from www.bbc.co.uk)

How can an imminent volcanic eruption take place without pre eruption signs??
as seen from the above pictures, Mt Merapi actually 'warned' the people by

• producing large amount of ash, gas and rock fragments before the eruption took place. The increase in volcanic activity took place 2 months prior to the eruption in 2006.
• The rising magma level in Mt merapi observed on the 1st may 2006 is also another tell-tale sign of the eruption.
• Furthermore, there is a noted increase in seismic activities in regions around Mt Merapi by triggering more than 150 tremors
• The increase in seismic activites happens as the magma flow melts and splits the basement rocks

hahaha short and sweet post eh? anyways, keep a look out for the next post.. which will hi-light the details of the eruption on 17th may 2006!

cheers for the annoyingly short entry! ^^

details of the formation of Mt Merapi!! ((:

Hi to all again!! ((:

the exact formation details!!

• As mentioned before, Mt Merapi is one of the many many volcanoes in the Pacific Ring of Fire (more about this later)
• It is formed by the collision of the indo-australian plate and the eurasian plate -- with the denser indo-australian plate subducting
• As the plate subducts, it is then dipped into the asthenosphere.
• With the incredibly high temperature at the asthenosphere, the cooler lithosphere (in this case, the indo-australian plate) will undergo partial melting
• With melting of the lithosphere, this "new magma" generated is less dense then the surrounding molten rocks due to the presence of sea water and external mineral
• The sea water lowers the temperature of the molten rocks in the over-riding plate (eurasian), making the rocks denser.
• This allows the "mew magma" to make its way up to the surface
• A chain of volcanoes are formed and Mt Merapi happens to be one of them!
• by the way, the type of lava produced by such a formation (i.e. the "new magma" ) is andesitic in nature
• Andesitic lava increases the danger of the eruption
• This is so as it is more viscous as compare to basaltic lava, hence,higher chances of hazards like ashflows and pyroclastic flows
• Eruptions are also more explosive and violent due to the build up in dissolved volatiles and pressure

  

** The next post will give you a better description and idea of the pre-eruption proccess. namely, how did Mt merapi behave? how did the people and government react?

Welcome back!

In this post, we shall dwell deeper into the mysteries of the infamous MOUNT MERAPI by learning about its formation.

As one of about 129 active volcanoes in Indonesia, Mount Merapi was formed by the subduction of the denser Indo-Australian plate beneath the Eurasian plate. To give u a better picture of what we are saying, we have provided(waddya know!) a picture of the plates below.

Moving on... let us take a look at the young, yet dangerously active volcanoe's most recent eruption...

The descriptions of the pre-eruption is a real-life account by a freelance reporter:

Background info: This account is dated May 6, 2006. Then, the alert level at Merapi was at 4, the highest possible level. Prior to this, plumes of hot gas, and lava flows had already heralded the coming of a major eruption

Pre-eruption account:

"Watching lava spill out of a volcano was arresting. I was arrested. Even from 6 miles away, its 2000 Fahrenheit glow knocked the wind out of me. A burning river tumbled down the mountainside, splashing orange bright beads like ocean spray along the way."

"As one of the flows turned toward us, I felt vulnerable as a blade of grass in a brush fire. Though I knew it probably wouldn’t make it even half the distance, I shuddered."

Judging from this reporter's description of an experience as harrowing and hair-raising as this, we all can guess that this eruption most probably won't just be yet another of the volcanoe's empty threats.

Mount Merapi
Wanna find out what happens next? Come back soon and read out next post to find out more about the pre-eruption period of Mount Merapi (2006)

The one that's closest to us -- Mt. Merapi (intro)

Hi to all!

Firstly we shall look at Mt Merapi in Indonesia... which actually erupted last year.

Some statistics of the volcano:

• Height: 2,914 metres
• Location: Central Java, indonesia --> part of the Ring of Fire
• Type of volcano: stratovolcanoes
• Type of eruption: peleean (lateral blast)
  
  
  
  

Mt. merapi "innocently" spewing ash and dust particles (pre-eruption)

Reasons why it is so dangerous (outlines):

• Periodic collapse of the lava dome results in the formation of nuee ardentes (more than any volcanoes on earth) and lahars --> main hazards
  
• Close proximity to densely populated areas -- 30km from Yogyakarta; rural villages located right at the foot of Merapi --> hence the hazards affect people DIRECTLY
  
• Mindset of the people - their unwillingness to evacuate despite the warnings issued by government

Lahars and pyroclastic flows burying a village

collapse of lava dome -- formation of nuee ardentes

** for the next post we shall look at the formation of Mt Merapi and take a closer look at the more recent eruption (ie 2006)

stay tune(:!