Category Archives: Other

Today in Geological History; July 9th -Lituya Bay

Standard

People of our generation have had the word tsunami seared on to our brains with the Boxing Day Tsunami and Japans March 11th tsunami claiming the lives of over a quater of a million people in the past 20 years. But what if these waves didn’t have the space of oceans to propogate  and instead where funneled though a confined space?

Killing an estimated 250,000 people the Boxing Day Tsunami hit maximum heights of 30 metres (100 ft) as it wiped out many coastal areas around the Indian Ocean. Before this event

Mg 6.2 Quake Rocks Central Italy

Standard

At the last report 37 people have been killed by a Mg 6.2 earthquake which struck just southeast of Norcia in Central Italy at 03.36 this morning.

Capture

Before and After shot of a street corner in Amatrice.

The area is prone to large earthquakes due to shallow normal faulting along a NW-SE oriented fault which runs through the Central Apennines. The region is tectonically and geologically complex, involving both subduction of the Adria micro-plate beneath the Apennines from east to west, continental collision between the Eurasia and Africa plates building the Alpine mountain belt further to the north and the opening of the Tyrrhenian basin to the west. It is the same fault which caused the controversial L’Aquila earthquake in 2009, just 45 km south-southeast of last nights event, which left 295 dead and saw 7 scientists prosecuted.

An aerial photo of Amatrice

The town of Amatrice taken by the local firebrigade.

The town of Amatrice has been mostly reduced to rubble although most of the dead have been found in the nearby town of Pescara del Tronto which has been completely levelled. Small towns like these are notoriously old or poorly built meaning even a weaker shallow quake can bring buildings crumbling down.

At least 39 strong aftershocks have hampered the rescue attempts many of which have be over a magnitude 4 and at least 1 reaching a magnitude 5.1

Italian president Matteo Renzi is currently addressing the nation saying that no area wil be forgotten in the relief effort.

I will add more as more information as it comes to light.

 

 

Figure 1; https://www.theguardian.com/world/live/2016/aug/24/italy-terremoto-earthquake-buildings-collapse-amatrice-rome-people-trapped

Figure 2; http://www.bbc.co.uk/news/world-europe-37171953

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

 

Today in Geological History; June 10th – Tarawera

Standard

Today marks the 130th anniversary of Tarawera bursting back to life after 500 years of sleep. It was one of New Zealand’s largest eruptions in recent history and killed up to 150 people making it the countries most deadly since the arrival of the Europeans.

Members of Te Arawa hapu Tuhourangi and Ngati Rangitihi will, weather permitting, make their annual pilgramage to the top of Mt Tarawera today for the 130th anniversary of the eruption.  Photo/File

Tarawara was last active in 1315 and is believed to have had a great hand in the Great Famine of 1315-137 throughout Europe. In 1886 the mountain gave little warning of up coming events. On June 1st a series of waves were recorded on the surface of Lake Tarawera suggesting seismicity in the area although no one reported feeling quakes and there where no seismometers at this time. Tourists claimed they saw a phantom canoe floating across the waters with Maori warriors on board. Although there were multiple accounts on the sighting many believed it was simply a rogue wave caused by increased seismicity, tribal elders at Te Wairoa however claimed that it was a waka wairua (spirit canoe) and was a portent of doom.

Charles-Blomfield-Mount-Tarawera-in-eruption-June-10-1886.jpgAll was quiet again in the following days and people though little of the complex. Many geologists at the time didn’t even consider the edifice to be active due to the lack of solfataric or fumarolic activity in comparison to New Zealand’s other volcanoes.

At 2am local time on June 10th this all changed. Locals where awoken by large tremors shortly followed by explosions heard as far away as Blenheim over 500 km to the south. by 2.30 all three peaks of Tarawera were eruption with fire fountains lighting up the pitch black, ash filled skies. The eruption began to the northeast side and spread rapidly along a fissure from Tarawera to Lake Rotomahana into the Waimangu Valley. The eruption was believed to be caused by a series of basaltic dikes which rose from depth and intersected the very active hydrothermal system under Tarawera and Lake Rotomahana, causing rapid steam/magma explosions, driving the plume that was observed and creating, by some accounts, fire fountains as tall as 2 km which explains the high explosively of a basaltic eruption.

The darkened skys were seen as far as Christchurch and was catapulted in the stratosphere where it lingered effecting climate for at least a year. The ash fall from the eruption – called locally the “Rotomahana Mud” – can be found into the Bay of Plenty almost 40 km away. This tephra covered 15,000 km2 over the North Island and over 4,500 km2 of the area with at least 5 cm of tephra.

The eruption itself produced at least 1.3 km3 of tephra (~0.7 km3 of dense rock equivalent), likely at a rate of higher than 6 x 104 m3/s. It also produced a base surge that travelled over 6 km from the craters moving 40 m/s and were large enough to top hills that were 360 meters tall which buried several Maori villages.

The Buried Village Rotorua

The Buried Village Rotorua is now a popular tourist destination often branded New Zealand’s answer to Pompeii. As well as the human impacts it also buried the Pink and White Terraces.

 

 

Figure 1; http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=11653679

Figure 2;  https://en.wikipedia.org/wiki/1886_eruption_of_Mount_Tarawera#/media/File:Charles-Blomfield-Mount-Tarawera-in-eruption-June-10-1886.jpg

Figure 3; http://www.visualitineraries.com/VisitPoint.asp?location=419&title=Rotorua+Museum+of+Art+%26+History

Figure 4; http://www.nzonline.org.nz/nzo/business/the-buried-village-of-te-wairoa-rotorua

 

 

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

 

Turrialba Eruption

Standard

Taking centre stage on many eruption blogs this week has been Costa Rica’s Turrialba volcano. It is one of the countries largest active volcanoes along side its neighbour Irazu.

Activity has been at moderate levels for a few weeks now with small explosions recorded daily and small lahars recorded on May 7th. At the begining of the week tremors appeared to decrease in both amplitude and frequency and the volcano appeared to be quietening down.

This quickly changed when a single explosion in the early hours of Thursday morning ejected a cloud of volcanic ash, gas and rocks from the volcano 30 miles east of the capital San Jose and saw local schools and businesses closed the next day. These have all since reopened however the alert remains at

Infrared video of eruption in the early hours of Thursday morning.

Figure 1; http://strangesounds.org/2016/05/turrialba-volcano-eruption-explodes-31-times-in-10-hours.html

Today in Geological History; April 25th – Nepal Earthquake

Standard

Today marks the one year anniversary of the Nepal Earthquake, sometimes referred to as the Gorka Earthquake where over 8000 people lost their lives. The initial quake, which struck approximately 85 miles west of the capital city, Kathmandu and registered at a magnitude 7.8. The shallow depth of the foci, just 8.2 km, lead to violent shaking which hit the maximum of IX on the Mercalli Intensity Scale.

Figure 1. Probably one of the most iconic pictures showing the rubble which was once a UNESCO world heritage site in Bhaktapur

The main earthquake struck at 11.56 am local time and was followed by a magnitude 6.6 just 34 minutes later. Aftershocks continued every 15-30 minutes for days with many hitting over Mg 4.5 hampering rescue efforts. Then on May 12th an earthquake struck further east along the fault line registering at Mg 7.3 killing an extra 218 people.

The Indian plate is currently crashing in to the Eurasian plate at a rapid rate of 45 mm per year, this is the same motion which has given rise to our planets highest mountains; the Himalayas.

As the Indian plate underthrusts the Eurasian plate it can get stuck leading to build up of stresses in areas which are relieved in the motion of an earthquake. Great Kashmir Earthquake of 2005 which claimed the lives of 87,000 people was  and the 1833 Kathmandu earthquakes were both created by the same build up of stress due to the plate collision.

The earthquake was felt over a vast area spanning 5 countries, but it was rural highland areas of Nepal which were worst affected. Landslide caused some of the worst damage. The Langtang Valley was hit by the largest single loss of life with a avalanche nearly 3 km wide sweeping down and burring an entire village. Smaller settlements on the outskirts of Langtang, such as Chyamki, Thangsyap, and Mundu were also buried. It is thought over 300 people died in the avalanche. The onset of the monsoon season soon after the earthquake killed even more people as the unstable ground was unable to hold up under the heavey rains causing further landslides.

Figure 3. Collapse houses in Sankhu, on the outskirts of Kathmandu

The earthquake also set in motion the deadliest disaster on Mount Everest since it was first conquered by Edmund Hillary in 1953. Everest is 220 km east of the earthquakes epicenter and was in the midst of its peak climbing season. Nearly a thousand people where on or around the worlds highest mountain at the time of the earthquake, including 359 climbers at Base Camp. Avalanches were triggered in several locations including one which originated on the nearby peak of Pumori which swept through South Base Camp through to Khumbu Icefall. 19 bodies were recovered from South Base Camp along with 61 stranded climbers. On 27 April, National Geographic reported the total killed on Everest was 24 although this figure has not been confirmed.

One year on Nepal is still struggling to recover. Thousands of homes were destroyed across many districts of the country, with entire villages flattened, especially those near the epicenter. 90% of the Napalese army were deployed to the region and within a week millions of pounds in aid arrived in aid from accross the globle, but after the initial rescue and clean up that appears to be the end of “relief”.

Capture

Table 1. Number of fatalities by county.

Rubble has been cleared and unstable buildings torn down, but virtually none of the 800,000 destroyed buildings have been rebuilt. According to the Red Cross over 4 million people are living in sub-standard temporary shelter.

With aftershocks still continuing and lack of outside aid it is fear life in the region will never fully recover. Nepal has always been known to be at great risk from tectonic activity in 2013, in an interview with seismologist Vinod Kumar Gaur, The Hindu quoted him as saying, “Calculations show that there is sufficient accumulated energy [in the Main Frontal Thrust], now to produce an 8 magnitude earthquake. I cannot say when. It may not happen tomorrow, but it could possibly happen sometime this century, or wait longer to produce a much larger one.”

Figure 4; The rescue workers ranged from locals to internation aid.

The Nepal earthquake was another stunning example of how some of the poorest countries fair the worst in natural disasters. With little or no building regulations cities like Kathmandu are left exposed and easily torn down by even relatively moderate quakes.

It could be generations before rebuilding truely begins in the region affected by the April 25th earthquake hopefully when the time comes lessons will be learnt and better measures be put in place.

 

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

Figure 2; http://reliefweb.int/map/nepal/nepal-epicenter-earthquake-25-april-2015

Figure 3; http://www.ibtimes.co.uk/nepal-earthquake-you-cant-rule-out-more-earthquakes-come-1500883

Figure 4; http://abcnews.go.com/International/americans-nepal-describe-massive-earthquake-devastating-aftermath/story?id=30580024

Table 1; https://en.wikipedia.org/wiki/April_2015_Nepal_earthquake