Tag Archives: News

Yadnya Kasada Festival

Standard

Since the dawn of man people have seen volcanoes as expressions of the rage of the God’s, punishments for poor behaviour on Earth. This was really brought home to me while working on Masaya last year. A huge cross now stands where, mainly women and children, were thrown in to the lava lake below as a sacrifice to the gods to spare the towns on the volcanoes flanks. Luckily human sacrifice is a thing of distant memories in most cultures but this does not mean people do not still worship at volcanoes.

Hindu devotees climb up to the crater of Mount Bromo.

The Tenggerese people are an ethnic minority in eastern Java who claim to be the descendants of the Majapahit princes. Predomintaly Hindu they have also incorporated many Buddhist and Animis elements. Yesterday marked the 14th day of their yearly festival Yadnya Kasada. Thousands flocked to the crater edge of Bromo to ask for blessing from the main deity Hyang Widi Wasa and Mahadeva, the God of the Mountain (Mount Semeru) by presenting annual offerings of rice, fruit, vegetables, flowers, livestock and other local produce

A Hindu devotee praysduring the Yadnya Kasada festival.

On December 5th last year Bromo’s PVMBG raised the volcano’s alert status to “siaga” (alert), or 3 on a scale of 1-4, it has remained around this till now with ash emissions continuing at fluctuating levels. Currently an ash column towers just under 1000 metres above the main vent, a sulphurous order lingers in the air. None of this however swayed the visitors eager for blessings. Many who ventured right up to the crater rim can be seen to wear rags around their faces to protect from the fumes, no effort was made to prevent people from entering the area.
The days of virgin girls meeting a fiery death may be long gone and now mainly goats and chickens lose there lives, but it is still shows the connections and respect people have for our planet and its power. This festival is not the only one world-wide which has a similar theme and I feel no matter the scientific findings about the inner working of our planet it will never deter such worship.

 

 

 

 

 

 

Figure 1; http://www.usatoday.com/picture-gallery/news/2016/07/21/the-yadnya-kasada-festival-in-indonesia/87385912/

Figure 2; http://www.usatoday.com/picture-gallery/news/2016/07/21/the-yadnya-kasada-festival-in-indonesia/87385912/

Figure 3; http://yourindonesia.arah.com/article/6681/upacara-yadnya-kasada-jadi-wisata-budaya-di-bromo.html

Figure 4; http://www.straitstimes.com/multimedia/photos/in-pictures-the-yadnya-kasada-festival-in-indonesia

 

Sinabung Claims More Lives

Standard

Sadly I awoke this morning to the news Mount Sinabung in Northern Sumatra, Indonesia had claimed the lives of three farmers working in the fields by the Gembar Village. This figure has since risen to 7 and is feared to continue to rise with several more critically injured and the Red Cross and army looking for further victims.

Mount Sinabung has been in a near constant state of eruption since late 2013. Pyroclastic flows sweep down its flanks on a regular basis which has lead to 4 km exclusion zone being enforced around the summit.  On February 1st 2014 people were killed by one such pyroclastic flows.

About 10,000 people have been displaced by activity at the volcano which has been on the highest state of alert for well over a year. Sadly the volcano is positioned in a relatively poor and over populated area of the world, many people have little choice but to continue to farm on the volcanoes fertile flanks. Officials have struggled to keep the people to stick the ‘red’ exclusion zones and it is unclear how many people were on the mountain at the time of the recent activity.

Head of the National Disaster Mitigation Agency (BNPB) Willem Rampangilei has instructed Karo Regent to take quick measures to vacate the red zones (Gamber village, Simpang Empat district and Karo Regency) but they know that this is easier said then done. The pyroclastic flows caused by partial collapses of the growing lava dome occurred in a series at 14:28, 15:08 and 16:39 local time on Saturday. Rescue attempts went through the night and in to Sunday morning. An ash column remained for hours, towering over the area darkening the skys and hampering the search operation.

The pyroclastic flow captured here to the left happened only a week ago on May 16th showing the power and regularity of such activity. On May 9th a lahar swept through  Kutambaru near the Lau Barus River killing 1 and leaving one person still missing now also presumed dead.

Sinabung lay silently for nearly 400 year until springing back to life back in 2010. It has now killed at least 25 people since its rousing. Volcanism on the island of Sumatra is caused by the subduction of the Indo-Australian plate beneath the Eurasian plate along the Sunda Arc which creates the andesitic-dacitic composition magmas which are prone to such explosive activity. Sinabung sits just 25 miles north-east of the Toba Super Volcano caused by the same tectonic motion.

 

Figures 1 and 2; posted to Facebook by SkyAlert.

Figure 3; http://www.volcanodiscovery.com/sinabung/news.html

 

What Makes an Earthquake ‘Significant’?

Standard
If you google “What is the definition of a significant earthquake?” you are met with Michigan Tech’s* response; Major – magnitude 7-7.9. However when looking at ‘significant’ earthquakes on the USGS** web page there are ones as low as magnitude 3.3. So to different people (and/or institutions) how we classify earthquakes seems to vary greatly and this occurs from top seismologists right through to media reporting and how we perceive the threat.

 

At 11.23 UTC on May 30th a Mg 7.8 earthquake struck off the coast of Japan. This is the same magnitude as that of Nepal’s April 25th quake but one managed to devastate an entire region and the other barely shook a few skyscrapers. Unless, like my self you concern your selves with the rumblings of our planet, or you live in Japan or the surrounding area you probably did not ever know last Saturdays earthquake even happened.

1. Aftermath of Nepal earthquake April 25th 2015.

The main difference between the two is the location of their foci. The focus of an earthquake (sometimes called the hyprocenter) is often confused with the epicentre, however the epicentre is the surface area directly over where the earthquake takes place, whereas the focus is the actual point at depth where the snap of energy takes place. With the Nepal earthquake the focus was just 15 km under a heavily populated region. The buildings on the surface were poorly built and unable to with stand the violent shaking, bringing them crumbling to the ground killing over 8000 people.

2. Displacement by Japan’s March 11th 2011 earthquake.

The Japan earthquake in contrast occurred off the coast, below the Pacific Ocean, although the some shaking was felt onshore. Many may assume this is safer than an earthquake under an urban area but several of the most deadly earthquakes occur at sea as they can induce tsunamis like that of March 11th 2011 which killed nearly 30,000 in Japan or the infamous Boxing Day Tsunami which killed as many as 230,000! Luckily on Saturday no tsunami alert was even issued, as the biggest difference between these two 7.8 earth quakes is depth.

Occurring at 677 km beneath the surface, this deep-focus (below 300 km) earthquake happened so deep its distance from focus to surface is only slightly shorter than travelling from London to Berlin (690 km)!!! As seismic waves travel they dissipate, loosing energy so are never as intense as what they are closer to the source.

3. Diagram of an earthquake, highlighting its focus and Epicenter.the waves lighten in colour with distance from the focus to show their loss of strength.

 

So so far we have magnitude, depth and location which impact on the devastation potential, but is there any thing else? Well we can expand on the last, location, to highlight other potential threats posed by an earthquake. A moderate sized earthquake in the heart of Los Angeles or Tokyo may stop the subway and send food flying off shop shelves but casualties should be low. The same earthquake in a country like Nepal or Haiti can kill thousands. Earthquakes don’t kill people per say, I have never heard of some on being shaken to death by a quake.What kills people is poorly constructed buildings collapsing, bridges failing, gas mains bursting causing fires. After past disasters such as San Fransisco’s great earthquake of 1906, wealthy countries which sit along active fault lines have put in place strict building codes and pumped millions in to disaster management programs and construction.   Obviously earthquake-proof is not always a possibility by earthquake-resistant definitely is and has saved the lives of many of the past few decades. Sadly not all at risk areas have that luxury of these safe guards at the expense of hundreds of lives.

4. Damage and fires caused by the Greath San Fransisco earthquake in 1906.

Seismology is a tricky business. With so much to take in to consideration when classify earthquakes, it is easy to see where there is often conflicting statements. Things are complicated further by the multitude of scales actually used to quantify them. When asked what scale is used, I can guarantee most will say the Richter scale (or local magnitude, ML), that is even what I was taught in school. Charles Richter first put his scale to use in 1935 to give a more scientific quantification for earthquakes than the previously used Mercalli scale which was solely based of human perspective and building damage (this is still used today but not as often). The Richter scale was limited in many ways being primed for nearby, mid-sized earthquakes (M 3-7). Seismologist Beno Gutenberg expanded on Richter’s work greatly enabling the scale to factor in greater distances and separated scales for surface waves (MS) and body waves (Mb).The revised scales still had difficulties and were particularly ineffective when looking at earthquakes which spanned great lengths of fault lines such the Aleutian Fox Island quake of 1952. The Richter scale was finally replaced by the Moment magnitude scale (MW) back in 1979 and this is the scale used by most institutes today including USGS.

Moment magnitude was born from elastic dislocation theory put forward in 1972 which suggests that energy release from a quake is proportional to the surface area that breaks free, the average distance that the fault is displaced, and the rigidity of the material adjacent to the fault. It is based on a similar logarithmic scale to the Richter scale with each step equating to an increase in the amount of energy released 101.5 ≈ 32 more than the previous. Earthquakes usually have similar Richter and moment magnitude numbers but rarely exactly the same and this can be one way one earthquake can be reported at different levels across the media if their sources used different scales. Another way which causes different figures  is precision; the more seismic stations used to calculate magnitude the more precise the result. When an earthquake is first recorded institutes are likely to only use their own data but as soon as they have access to the global seismic network they can give a more accurate classification. This happen with Japan’s earthquake on May 30th, initial reports put it over a magnitude 8 but this was quickly downgraded to 7.8.

As you can see an earthquakes significance is a matter for debate and in many cases personal opinion. Magnitude and location (not just geographically but also politically) are the main factors but it tends to vary earthquake to earthquake.

Station VRI seismogram

5. Example of a seismograph.

 

Nepal Earthquake

Standard

I sat in a bar last Thursday night discussing the rarity of large-scale natural disasters with several of my non-geologically minded friends. They were shocked to hear just how common certain hazards actually were. I explained that media coverage is scarce depending on fatalities or area of the occurrence, but we have actually been lucky not to have seen any particularly deadly events in a while. Sadly I spoke to soon…

Figure 1. Remains of the Bhaktapur temple, once a UNESCO world heritage site

At 11.56 am local time (06.11 UTC) Saturday, Nepal was rocked by its strongest earthquake in decades. The Mg 7.8 quake was intensified by its shallow depth, just 11 km below the surface, meaning waves had less time to dissipate and disperse leaving the region to feel its full force. This morning officials have raised the estimated death toll again to just under 4000 but it could be weeks before we have real figures. The rescue operation has been hindered by hundreds of aftershocks many over a Mg 5 and even several over a Mg 6 making them devastating events in their own right.

The effects where far-reaching with all neighbouring countries feeling the tremor. India has so far reported 67 deaths and China and Bangladesh 20 and 8 respectively. 19 people lost their lives on Mount Everest as the quake induced avalanches across the snowy region. It is the mountains highest fatality since explorers began ascending its flanks in 1953, scores of hikers are still believed to be stranded.

Figure 2. South Base camp was struck by an avalanche soon after the earthquake killing 12

Why has this earthquake been so devastating?
The answer is a combination of two factors;

Firstly the region is extremely tectonically active. The processes that caused this earthquake are the same that have given rise to the highest mountain range on the planet, the Himalayas. The Indian plate is moving north-northwest towards the Eurasia plate at a rate of 40-50 mm per year. The thick continental crust of the Indian plate instead of simply subducting under the Eurasian plate in to the mantle, like oceanic crust would, actually lifts the opposing plate creating the Himalayan mountain range. Large scale earthquake are relatively common along the subducting surface of the Indian plate as it sticks to the overriding plate, there have been 4 in the last century including Saturdays event. The largest was a Mg 8.0 back in 1934 roughly 240 km southwest of the recent quake; over 17,000 lost their lives. The last was back in 1988 claimed nearly 1500.

image

Figure 3.

Secondly despite all this knowledge the country and many of its neighbours are grossly unprepared for such events. Nepal is one of Asia’s poorest countries, many of its residents live in extremely poorly constructed buildings and in many cases shacks. Building codes and regulations in place in richer at risk regions, say San Francisco, are simple non-existent in the Himalayan region. The epicenter was just 77 km north-west of the countries densely populated capital Kathmandu, were it’s believed at least 800 have lost their lives. Surrounding villages have seen complete devastation with no building and very few people surviving.

Figure 4. Huge displacement due to the quake.

Only last month at the UN World Conference on Disaster Risk Reduction identified the potential threat in the region but no further measures were put in place. Hopefully when the rebuilding process begins steps will be taken to limit the threat of future earthquakes.

Figure 1; http://www.theguardian.com/world/live/2015/apr/26/nepal-earthquake-death-toll-exceeds-1500-rolling-report

Figure 2; http://unofficialnetworks.com/2014/04/12-confirmed-dead-everest-avalanche

Figure 3;

Figure 4; http://www.cidi.org/disaster-responses/nepal/#.VT5EMpMYGuQ

Eruptions Updates

Standard

Villarrica, Chile

Villarrica has become the Kim Kardashian of volcanoes with stunning images of its recent activity flooding the internet. Fire fountains have sent ash and lava up to 1000 ft in to the air and light up the skies of Southern Chile for the past few days.

The volcano has been restless for several weeks now, with small bombs and scoria blocking the usual tourist hike round the crater lake. So far about 3,500 people have been evacuated from the flanks, predominantly the residents of Pucón a popular tourist destination.

Although the fireworks appear to have calmed down, seismicity remains high indicating Villarrica has not finished clearing his throat.

Bardabunga, Iceland

The other big volcanic news this past week comes with the end of the blogs most covered lava field at Holuhraun. On February 29th the Icelandic Met Office released a statement that the fissure eruptions has come to an end as there appears to be no lava output since mid February.

 

More in depth updates soon to follow.

Mg 6.9 Iwate and Tsunami warning

Standard

At 8.06 am local time a magnitude 6.9 submarinal earthquake occurred of the coast of Iwate, Japan. JMA have claimed it is an after shock from the mg 9, March 11th megathrust quake in 2011.

The following tsunami alert was released although this was played up by some media stations to a full blown warning.

This Tsunami Warning/Advisory was issued in the past
Occurred at 08:06 JST 17 Feb 2015
Region name Sanriku Oki
Depth about 10 km
Magnitude 6.9
Click the map to zoom in

Tsunami Forecast Region Category of Tsunami Warning/Advisory
IWATE PREF. TSUNAMI ADVISORY

Tsunami Warnings / Tsunami Advisories

Issued at 08:09 JST 17 Feb 2015

******************Headline******************
Tsunami Advisories have been issued for the following coastal regions of Japan:
IWATE PREF.

*******************Text********************
Tsunami Advisories have been issued for the following coastal regions of Japan:
<Tsunami Advisory>
IWATE PREF.

***********About Tsunami Forecast************
<Tunami Advisory>
Marine threat is in place.
Get out of the water and leave the coast immediately.
As the strong current will continue, do not get in the sea or approach coasts until the advisory is cleared.

<Tsunami Forecast (Slight Sea Level Change)>
Though there may be slight sea-level change in coastal regions, no tsunami damage is expected.

******* Earthquake Information ********
Occurred at 08:06 JST 17 Feb 2015
Region name SANRIKU OKI
Latitude 39.9N
Longitude 144.5E
Depth about 10 km
Magnitude 6.9

The following arrival times were issued;

Tsunami Forecast Region/
Tsunami Observation Site
High Tide Time Estimated Initial
Tsunami Arrival Time
<Tsunami Advisory>
  IWATE PREF. ( Area where tsunami is
expected to arrive first )
08:30 JST 17 Feb
    Miyako 13:28 JST 17 Feb 08:40 JST 17 Feb
    Ofunato 13:36 JST 17 Feb 08:40 JST 17 Feb
    Kamaishi 13:36 JST 17 Feb 08:40 JST 17 Feb
    Kuji-ko 13:23 JST 17 Feb 08:50 JST 17 Feb

The warning was then terminated at 10.21 local time.

Current Volcanic Activity; New and Updates.

Standard

Sinabung

Just moments after posting this originally images came through of a pyroclastic flow at Sinabung at 14.05 GMT.
image

Fogo

Finally I have found a half decent update from the Global Volcanism Program albeit for about a week or two ago. By the 6th January the lava front had stalled in areas near S Ilheu de Losna where as was still advancing at a slow rate in the northern end of the town. Houses are still being overtake by the flow but decreasing temperatures of the lava means we could be nearing an end to the destruction. For the first few days of the month sulfur dioxide emissions were averaging at 1200 to 1300 tonnes a day.

Etna

Etna saw out 2014 with some pretty explosive activity on the 29th December. The new southeast crater had consistent but small emissions and incandescents. Explosions intensified on the 2nd and 3rd sending material 150 meters above the crater rim and an ash plume which traveled southwest.

Activity has been pretty on going since December 28th and shows little sign of slowing. On January 1st and 2nd, strombolian activity was seen at th Voragine crater, which has been inactive for over two years.

HungaTonga-HungaHa’apai

Based on pilot observations an ash plume rose to just over 10,000 ft on January 6th.  This is the first notable activity at the volcano since 2009. The main caldera is submarine.

Soputan

Darwin VAAC reported that a ‘significant’ eruption began at 14.47 local time on January 6th.  A lava flow has travelled 2 km down the WSW flank although no warnings have been issued. An ash plume rose to roughly 27,000 ft how ever nothing can be detected on satellite imagery due to poor weather conditions. The alert remains at 3 on the four point scale.

Bárðarbunga

As of January 5th the lava flow now covers an area just over 83 square kilometers. although the overall intensity of both flow and seismicity is less then a few months ago, the fissure eruption shows no sign that it is coming to an end.

""

Tangkubanparahu

On December 31st the alert d 2 and local residents were warned not to go within a 1.5 km radius of the crater. White plumes has been drifting from the Ratu crater since late November, but an increase in seismicity and ground deformation has led to the apparent rise in threat.

Sheveluch

KVERT reported a lot of strong activity at Sheveluch towards the end of December including incandescent avalanches and fumerolic activity. The aviation code was kept at orange as an ash plume travelled both 60 km westwards and over 370 km ENE. Satellite images indicate a thermal anomaly over a new lava dome on the northern flank.