Mount Rainier is a glacial covered stratovolcano situated on the western seaboard of the USA. It is the highest of the peaks at 4392 m in the Cascade Range and my personal favourite of the Decade volcanoes.

With its towering position over the cities of Seattle and Tacoma it is seen a great hazard of the future, particularly with threat of lahars because of the large amounts of ice, and snow on its flanks and summit. This is the major reason for its inclusion as a Decade Volcano. However there are other hazards, in the past debris avalanches caused by the collapse of part of the edifice have travelled very long distances and can reach as far as the Puget Sound. An event such as this occurred around 5600 years ago in a similar but larger event to that which occurred at St. Helens in 1980. Of course a large eruption of Rainier would also be accompanied by the usual ensuing volcanic hazards (Pyroclastic Density Currents, Ashfall, Lava flows).

The main edifice is around 500,000 years old and is composed of mostly lavas which have built up over time.  It is unclear when Rainier last event minor event was with different souces stating different things! According to the GVP an event occurred back in 1894 which involved minor activity at the summit. It has been a while since any major activity has been seen, with up to VEI 4 events occuring in the past as is shown on the GVP. With a volcano such as Rainier any future eruption it is highly probable that it would be preceeded by warning signs such as deformation, hydrothermal activity and degassing increases. Despite the location of Rainier, there is a lot more work to be done on the volcano to understand its history and hence its potential future!

I am afraid that posts will be a little more sparse and irregular over the coming months due to an extremely busy summer (getting married and a dissertation to complete!), however I should get back to regular posting by the end of July!

Sources
USGS
Global Volcanism Program
Sisson, T.W., 1995. History and Hazards of Mount Rainier, Washington. USGS. Open-File Report 95-642.

Nyiragongo, famous for its almost constant lava lake within the summit crater, it is a stratovolcano of the Virunga Volcanic complex in the East African Rift Valley and is probably the most dangerous in Africa. In total there are 8 mountains in the complex however Nyiragongo and the nearby Nyamuragira (picture below) are the only ones which remain active today.

The two most important and devastating eruptions of Nyiragongo occurred in 1977 and 2002, both of these eruptions caused many fatalities. The eruption in 1977 completely  and rapidly drained the lava lake on the 10th January 1977 creating rapid lava flows (up to ~60 mph in some cases) this rapidly overwhelmed the flanks and displaced many people present in Goma and on the flanks of the volcano. The lava lake then began to refill and on January 17th 2002 another eruption occurred when a fissure initially propogated from the top of the volcano (and later from the base) allowing the outflow of lava, the length of fissures totalled almost 20 km. Lava fountaining (or Hawaiian activity) was also present during this eruption.

Another youtube video gives an excellent overview of the area around Nyiragongo and the eruption of 2002, available here.

Sources
Shuler and Ekström, 2009. Anomalous earthquakes associated with Nyiragongo Volcano: Observations and potential  mechanisms. Journal of Volcanology and Geothermal Research 181 (3-4), pp. 219-230

Mavonga et al. 2010. Studies of crustal structure, seismic precursors to volcanic eruptions and earthquake hazard in the eastern provinces of the Democratic Republic of Congo. Journal of African Earth Sciences 58 (4), pp. 623-633

Global Volcanism Program
John Seach
Nasa EOS  

Quick eruption update: Actvity at Nabro has increased somewhat with the production of a new plume reported at Irish Weathre Online and by the Toulouse VAAC. This plume however is severely lacking in ash (evidenced by it's white colour) and contains large amounts of Sulphur Dioxide. For a detailed update please visit the Volcanism Blog for discussion and pictures! The eruption in Chile of Puyehue-Cordón Caulle is also causing major diruption to air travel as it continues. Whilst the renewed activity at Bocca Nuova on Etna continues with light ash emissions - from @etnaboris.

Merapi which has featured heavily in the news recently, is one of the most active volcanoes of Indonesia, but more importantly one of the most hazardous in terms of threat to human life, hence it's designatin as a Decade Volcano. Mythology is very important to the locals around Merapi, who generally believe that Merapi is housed by spirits in various guises.

Merapi, in central Java, is a stratovolcano which stands at ~2968 m tall. Due to the large amounts of people living within it's hazardous reach the Merapi Volcano Observatory keeps a watchful eyeover it's activity. It is the youngest of the volcanoes in the Java area and produces eruptions every 1 to 5 years of an andesitic type.

The main hazards faced from eruptions of Merapi are the formation of Pyroclastic Density Currents (also called Pyroclastic Flows etc), a number of these are shown in the photos below, and lahars. Lava dome formation also occurs within the crater of Merapi and the collapse of these domes has caused the formation of Pyroclastic Density Currents frequently in the past. The most recent 2010 eruption has caused the deaths of more than 300 people. However the most devestating eruption occured in 1930 when more than 1000 people were killed by Pyroclastic Density Currents.

Sources
Global Volcanism Program
John Seach

Below is an unusual and amusing email I recieved via the contact form which I thought  I would share with everyone. It certainly gave me a chuckle!
 
Email Starts
I have heard the following theories about the eyjafjallajokull
eruption and would like youre opinion on the events....
 
1. A meltdown of the Sun activated the volcano
2. Secret experiments with ‘seismic weapons’
3. Closing in on the end of the Mayan calendar
4. Manoeuvres at an alien landing site
5. Discreet terror attack response exercise
6. The Earth is beginning to heal itself
7. Preliminary warning of a mega poison cloud
8. Beginning of a new super eruption
9. The interior of the Earth is collapsing
10. Fulfilment of age-old Nordic legends

Thanks

Dr. Ignim Brite
Email Ends

Which one is your favourtie? Let me know!

Mauna Loa, a shield volcano of Hawaii, is the largest volcano on Earth with a volume of 80,000 km2. At ~4170 m above sea level it is not the tallest, however when you take into account the ~5000 m it stretches from the sea bed to sea level a grand total of more than 9000 m is obtained, which, if it wasn't for its neighbour Mauna Kea (at ~10,000 m) would make it the tallest volcano as well! Due to its size and weight it has also pushed down its base by a further 8 km, not a true height, but extremely interesting! 

This volcano was formed by a mantle plume (or hot spot) and evidence of the plume position can be seen at the surface and in the sea as the Hawaiian-Emperor Seamount Chain. As the Pacific plate moves and the mantle plume stays in roughly the same area a series of islands is created. In geological time, Mauna Loa is also relatively young at 200,000 years old and will probably become extinct within the next 500,000 to 1 million years.

At the summit of Mauna Loa is the current Mokuaweoweo caldera around 5 km long and 3 km wide within an older and larger caldera. The last eruption of Mauna Loa occured in 1984 and was characterised by the usual mild explosive and effusive characteristics that are commonly seen on Hawaii. This included lava flows (aa and pahoehoe), hawaiian acitvity (fire fountaining) and strombolian activity.

This post has probably not done Mauna Loa justice as it is an extremely interesting volcano with a more diverse history than can be fit into one post! There are many good sources of info including the Global Volcanism Program and the Hawaiian Volcano Observatory.