Category Archives: Today in Geological History

Today in Geological History; June 15th – Mount Pinatubo 1991

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Figure .1 Mount Pinatubo 1991

Before the eruption in the early 90’s, Pinatubo was a rather unassuming mountain on the island of Luzon, Philippines. Standing only 2000 ft above surrounding peaks, it was almost obscured from vision. It’s flanks covered in lush green forest, without an eruption in memorable history, people never saw it as a threat.  This change in June 1991 when it produced the second largest eruption of the 20th century (after Novarupta 1912).

Figure 2. Damage from the earthquake in 1990.

In 1990, on July 16th a magnitude 7.8 rocked the island of Luzon. A strike-slip along the Philippine Fault System it caused a surface rupture oer 125 km long. Killing  over a thousand people it became the deadliest earthquake in Philippine history but may also have been the start of something much greater, geologists have long been convinced that it is linked to Pinatubo’s activity the following year. However it has never been proven if this earthquake stirred the sleeping volcano or if the reawakening caused the quake. For a few weeks after locals reported steam coming from Pinatubo, but when it was visited by PHILVOLC’s scientists there was only landslide evidence and not emissions.

Seismicity kicked off activity again on March 15th 1991. The north-west side of the volcano felt a swarm of tremors increasing in intensity over the next two weeks. On April 2nd a 1.5 km fissure opened along the summit with phreatic explosions dusting the local area in ash. seismicity continued to increase causing volcanologist to rush to its flanks to place monitoring equipment they had never thought to place while the mountain lay in slumber. The volcanoes eruptive history had very been studied before and they were surprise to learn it had large eruptions as recent as roughly 500, 3500 and 5500 years ago. On April 7th the first formal evacuations took place. With the Clark Air base just 14 km from Pinatubo the USGS aided PHILVOLCS in setting up 3 zones the first, a 10 km radius from the summit was the initial area to be designated unsafe and people were quickly evacuated to safety. Further zones from 10-20 km and 20-40 km were deemed safe for now but people were told to be alert to the possibility of evacuation if the mountain showed any sign of getting worse.

Figure 3.

Activity stepped up in May with sulfur dioxide emissions rocketing from roughly 500 t p/d at the beginning of the month to over 5000 t p/d by May 28th. At this point emission slightly decreased and inflation began to increase rapidly leading many to believe pressure was building with the magma chamber.

On June 3rd the first lava was noticed signalling that a magmatic phase of the eruption had begun which eased some people’s mind as activity seemed relatively effusive. The first large explosion cam four days later on June 7th. An eruption column towered 7 km above the summit prompting the second wave of evacuations with people in the 10-20 km zone being prompted to leave their homes. A lava dome began to grow dramatically in the next few days reaching in excess of 600 ft wide. Activity seemed pretty constant at a low-level until 03:41 on June 12th when a new, more violent phase of eruptions began. As explosions intensified over the next few hours the eruption column grew to over 19 km. Pyroclastic flows surged as 4km from the summit in some valleys. Ash and tephra rained down on the surrounding area as the intense explosions lasted over  . The final wave of evacuations was called for on the morning of June 13th as a small but intense earthquake swarm saw in a third phase in the eruption.

Figure 4. On of the most iconic images from the 1991 eruption.

People as far as 40 km away, and even further if possible, were urged to leave the area as quickly and calmly as possibly as Pinatubo showed no signs of slowly down its activity. The column peaked again, this time over 24 km high. Several more large explosions were recorded for the next 24 hours including one at lunch time on the 14th with saw another 21 km eruption column and more pyroclastic flows obscuring the view of the flanks.

From midday on June 15th the eruption reached its most climatic point. By 2.30 pm on the June 15th readings stopped being received from seismometers and other remote censoring equipment which the USGS had placed at Clark Air base indicating the area had been over some by the pyroclastic material still being ejected at a terrifying rate. An ash cloud covered an area greater than 125,000 km2 bringing near total darkness to much of the island of Luzon and ashfall was recorded as far as neighbouring countries of Cambodia, Malaysia and Vietnam. By 10.30pm that night all fell quiet and Pinatubo’s fury seemed to be over.

Figure 5. Mapping the spread of the SO2 released by Pinatubo.

The VEI 6 eruption spat out over 10,000,000,000 tonnes of material and a whopping 17,000,000 tonnes of sulphur dioxide. It was the later which signed Pinatubo’s fate in people’s minds as the SO2 emitted quickly covered the globe causing the mean global temperatures to drop by 0.5°C for the following two years. Sulphur dioxide in the atmosphere reflects the Sun’s radiation back in to space meaning the Earth’s surface received up to 10% less sunlight in the following year. It also meant an increase in ozone damage, with the hole above the Antarctic being at the largest it had ever been.

An estimated 847 people lost their lives (many from collapsing buildings under the weight of the ashfall),but problems continued past initial fatalities in the aftermath. Over 2.1 million people have believed to have been affected by the disaster. Agriculture was severely effected both my ash fall and then following effects of the climate. Lahars plagued the region for years after with each heavy rain fall. It is often put by the end of 1992 the eruption and resulting lahars caused the country losses in excess of 400 million US dollars.

Despite this, the events of 1991 are often hailed a volcanological triumph with quick responses, prediction and evacuation believed to have saved the lives of thousands. It enabled us to gain an insight to volcanic impacts on climate and how we monitor the risks.

Figure 1. http://www.slate.com/articles/life/welltraveled/features/2012/tempting_fate_in_the_philippines_/dennis_rodman_s_dad_and_the_eruption_of_mount_pinatubo_.html

Figure 2. http://xuwenewegu.webatu.com/earthquake-in-philippines-july-25-2011.php

Figure 3. http://www.coolgeography.co.uk/GCSE/AQA/Restless%20Earth/Volcanoes/Mount%20Pinatubo.htm

Figure 4. https://www.uclm.es/profesorado/egcardenas/pa.htm

Figure 5. http://earthobservatory.nasa.gov/IOTD/view.php?id=1510

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Today in Geological History; June 10th – Tarawera

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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

 

 

Today in Geological History; June 3rd – The 25th Anniversary of Unzen

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Today marks the 25th anniversary of the pyroclastic flow from Mount Unzen which claimed the lives of 43 people.

Mount Unzen

Mount Unzen is actually several over lapping volcanoes on Japan’s island of Kyushu. It was the cause of Japan’s largest ever volcanic disaster in 1792 when a lava domed collapsed and caused a mega tsunami which killed nearly 15,000 people. After this even the volcano lay silent until beginning to stir in 1989.

Seismic swarms began in the November of 89 about 10 km west of the summit and gradually migrated eastward until the first phreatic eruption a full year later in November 1990. By May 20th 1991 fresh lava began to flow from the highly inflated summit area prompting the evacuation of almost 12,000 locals.

volcano-unzenThe threat of another eruption to the scale of 1792 brought journalists and scientists alike flocking to the surrounding area to monitor the activity of Unzen and its potential threat. Sadly this curiosity resulted in the deaths of 43 when on June 3rd activity peaked due to a possible lava dome collapse. This sent a huge pyroclastic flow surging down its flanks and funnelled in to a valley point in the direction where volcanologists and journalists had set up a base at what was thought to be a safe distance, over 4.5 km, from the summit.

Activity continued well in to 1995 and over 10,000 pyroclastic flows were recorded over this period. By the end of the eruption a new lava dome was in place 1.2 by 8 km wide. Its volume was approximated at 0.1 cubic km.  In total, about 0.21 cubic km of plagioclase-phyric dacite magma was erupted over the course of the eruption at peak effusive rates of 7 cubic metres per second in 1991. Over 2000 buildings were destroyed by these flows in Shimabara City alone. Matters were further complicated between August 1992 and July 1993 when heavy rains caused multiple lahars destroying a further 1300 homes along the Mizunashi and Nakao Rivers, requiring the sudden evacuation of several thousand residents.

Mount Unzen has been placed on the official decade volcano list and is one of Japan’s most highly monitored areas.

Maurice and Katia Krafft

The Krafft’s were French volcanologists and soul mates who met at the University of Strasbourg. Their love for volcanology almost reviled their love for each other. The specialized in documenting eruptions as best and often as close as possible, their end was almost inevitable.

Their most famed contribution was the documentation of Nevado del Ruiz which when shown to the Phillipine president Corazon Aquino who was then convinced to evacuate the area surrounding Mount Pinatubo before its catastrophic 1991 eruption almost certainly saving hundreds if not thousands of lives. 

Over a 20 year period, when volcanology was still a relativity young science, the married couple documented hundred of eruptions. They fillmed over 300 hours of footage, took thousands of photos and published multiple books.

While in the Philippines during Pinatubo’s early stages, Maurice was interviewed by a local news agency where he told the journalist  “I am never afraid, because I have seen so much eruptions in 23 years that even if I die tomorrow I don’t care.” From here they flew out to Japan where activity was picking up at Unzen. The pair perished together when they were overcome by the pyroclastic flow on June 3rd.

Harry Glicken

Man wearing a coat and hat and holding a pad of paper sits on a rock , with a lake and several mountains visible in the backgroundHarry was an American volcanologist who although was based at USGS was funded by outside organisations. He specialised in volcanic debris flows and was closely involved with research on St Helens with his doctoral thesis ‘Rockslide-debris Avalanche of May 18, 1980, Mount St. Helens Volcano, Washington‘ being recognised as a leading paper on the event.

Glicken cheated death on St Helens as he was meant to be the volcanologist on duty May 18th however swapped with his then mentor David Johnston who was killed by the blast.

Figure 1; http://raredelights.com/top-28-worlds-important-volcanoes/mount-unzen-in-japan/

Figure 2; https://curiousmatters.wordpress.com/2014/05/23/curious-facts-31-of-the-strongest-volcanoes-known-to-man/

Figure 3; https://en.wikipedia.org/wiki/Mount_Unzen

Figure 4; https://volcanogeek.wordpress.com/2011/09/20/maurice-and-katia-a-love-story/

Figure 5; https://en.wikipedia.org/wiki/Harry_Glicken

Figure 6; https://www.youtube.com/watch?v=Cvjwt9nnwXY

 

 

 

 

Today in Geological History; April 25th – Nepal Earthquake

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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

Today in Geological History – March 27th; The Great Alaskan Earthquake

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The second strongest earthquake ever recorded occurred at 5.36 pm AST (3.46 am 28/03 UTC) on Good Friday in Prince William Sound, Alaska. Registering a massive 9.2 on the moment magnitude scale, it shook the region for 4 and a half minutes and generating a tsunami which propagated through out the Pacific Ocean.

The Pacific Plate moves northward and subducts under the North American plate along the northern edge of the Pacific Ocean creating a highly seismic zone and the explosive volcanics of the Aleutian Islands. On March 27th 1964 the Pacific Plate jolted forward in a megathrust earthquake causing major vertical and horizontal displacement in an area spanning over 250,000  km

At the time of the earthquake Alfred Wegener’s theory of plate tectonics was only just being proven by surveys of the worlds oceans. Although the study of seismology and the several large subduction earthquakes which happened in this era helped prove the theory it meant little was understood about the mechanics of megathrust earthquakes (a termed created in the wake of the Great Alaskan Quake). Earthquake resilient building standards where  at the time and all where unprepared for  the events of the Easter weekend.

At a depth of just 23 km the focus was just 125 km northwest of the states capital Anchorage which took most of the damage.It hit a high of XI on the Mercalli Intensity scale, the second highest mark, indicating the intensity of the shaking experienced in the area. The shaking tore apart buildings and subsidence ripped apart roads. Anchorage was built on sandy bluffs and clay, the earthquake caused a landslide which buried 75 homes. The control tower at Anchorage International airport was reduced to rubble.

139 people lost there lives, mainly due to the tsunami which badly hit much of the Alaskan coastline but also claimed lives as far away as Crescent City, California where 12 were killed. At its maximum the tsunami reached as high as 220 ft in Shoup Bay, but most were much smaller. Alaska was actually hit by multiple tsunami, one caused by the earthquake itself and then several local smaller waves up to hours later prolonging the suffering and hampering rescue operations.

The Great Alaskan Earthquake changed much of our understanding of the sheer power of our planet, which rang like a bell with vibrations for days after. Waterways as far south as Texas sloshed from side to side as the seismic waves where felt throughout the continent.

USGS worked quickly to collect data, recording the subsidence and uplift in the region. They began to see how secondary faults accommodated the erratic displacement. They also began to form a much clearer picture of the Aleutian Trench where the Pacific Plate subducts cementing the idea of plate tectonics. It also shone light on the major part soil liquefaction had in the destruction of the area. Core samples taken along the Copper River indicated that the Good Friday was not the first megathrust event in the area. Analyzing just 50 ft cores scientists revealed evidence of 9 megathrust earthquakes in the past 5,500 years.

The events of March 27th lead to the USGS beginning installation of an extensive earthquake-monitoring network across Alaska as part of the Advanced National Seismic System. In 1966 the National Earthquake Information Center was established as apart of the US Coast and Geodetic Survey and was transferred to USGS control in 1973. By 1977 Congress passed the Earthquake Hazards Reduction Act, the world was beginning to take the threat seriously.

Figure 1; https://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&ved=&url=http%3A%2F%2Fwww.theoildrum.com%2Fnode%2F8573&psig=AFQjCNHCK3Uk0lxyjJZhA8t2fmQn_Kq8iQ&ust=1459094529661721

Figure 2; http://earthquake.usgs.gov/earthquakes/events/alaska1964/

Figure 3; http://www.wired.com/2009/07/tsunami/

 

Today in Geological History; March 11th – Tōhoku Earthquake & Tsunami

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article-0-0D924D9F000005DC-785_964x591.jpgI am pretty sure I have covered this event before but seeing as today marks the 5 year anniversary of one of the worst natural disasters in the past decade I thought it deserves a much more in depth look. The events of March 11th destroyed the lives of hundreds of thousands of people and claimed the lives of nearly 20,000. For me, it opened my eyes to a world of geohazards and mad me realized this was something I wanted to study and understand so such loss of life would not happen again.

There are three elements to the events of March 11th that I am going to look at here; the earthquake, the tsunami and the Fukushima power plant. Each aspect a huge disaster in on there own but interlinked as they were caused devastation for Japan. 

The Earthquake

Instrumental Intensity Image

Japan is a volcanic island which stretches along where the North American, Pacific, Eurasian and Philippine plates all collide at different points. It is a part of the Pacific Ring of Fire, the world’s most tectonically active area. Practically all of our planets largest and most destructive earthquakes occur along the ring, one of which rocked the east coast of Japan at 2.46 pm JST (5.46am UTC) on March 11th 2011.

The magnitude 9 quake struck at the shallow depth of just 32 km roughly 70 km off the Oshika Peninsular. The area was already alert to seismic activity as several large foreshocks had occurred in the run up including a Mg 7.2 on March 9th and followed by three more above a Mg 6. Of course no one knew these were precursors to something much larger…

Initial reports from JMA and USGS put the March 11th quake at a 7.9 but this had risen first to a 8.8 and then to a 9 before most of the seismic waves had even hit Tokyo 373 km away. Luckily thanks to Japans intense seismic network the countries capital had at least 80 seconds warning before they felt the strong shaking.

The megathrust earthquake occurred where the Pacific Plate subducts beneath the North America Plate. The Pacific Plate moves at a relative speed of roughly 9 mm per year but it is not a smooth decent, tension can build and release in a large snap causing an earthquake. On March 11th this happened in epic style causing over ~50 meters of displacement near the Japan Trench which caused the tsunami which swept across the Sendai planes. The earthquake was so powerful that up to 1.69 meters of co-seismic deformation has permanently altered our planet and affected the Earths tilt shaving 1.8 microseconds of the day (not that we would ever notice!)

It was the forth largest earthquake ever recorded and the largest ever to strike Japan.

The Tsunami 

The displacement on the sea bed in turn caused a huge displacement of water in the Pacific ocean its self. Across a 180 km stretch there was recorded up thrust of 6-8 meters. Above the rupture the tsunami waves would have looked like no more than ripples on the surface radiating out across the ocean. It is as the waves reach the continental shelf and the water is forced upwards that they begin to take on their characteristic ‘wall of water’ appearance.
At its maximum height (recorded at Miyako, Iwate) the waves hit 40.5 m high (133 ft). The Pacific has the most comprehensive tsunami warning systems in the world but even this gave only about 15 minutes warning from the earthquake to waves hitting the coast line. Travelling at speeds up to 500 mph the water surged up to 6 miles (10 km) inland.

Honshu earthquake tsunami travel times

It was not just Japan which felt the repercussions of the event. Tsunami waves propagated out through out the entire Pacific. 11,000 miles away the coast of Chile experienced waves in excess of 2 meters along with most of the America west coast right up through to the Aleutian Islands and as far south as Antarctica where it broke chunks off the Sulzberger Ice Shelf

An estimated 5 million tonnes of debris began washing up on shore lines across the Pacific in the months and even years after the initial Earthquake. In April 2013 a 20 ft boat ran aground in California and was later identified as belonging to the marine sciences program at Takata High School, Japan. NOAA have kept tracks and aimed to clear as much of the debris as possible to minimize risk to ships and wild life but the operation can take more than a decade.

Fukushima

The melt down at the Fukushima was the worst nuclear disaster the world has seen since Chernobyl in 1986.

The plant ran by TEPCO had 3 of its 6 units shut down for inspection when the earthquake struck. Units 1, 2 and 3 then under went automatic shutdown cutting off power. 50 minutes later the waves up to 15 meters high breached the measly 5.7 meters seawalls and flooded the basements of the turbine buildings and disabling the emergency generators. The lack of power meant the cooling systems of the 3 active reactors failed and eventually the heat caused by decay caused the containers to burst leaking radioactive material.

It was classified a Level 7 on the International Nuclear Event Scale (INES) and its was the way the event was handled from the very beginning my TEPCO which saw the escalation in the threat. Approximately 15 PBq of caesium-137 was released along with some 500 PBq of iodine-131, luckily all the failed reactors were in concrete containment vessels, which limited the release of strontium-90, americium-241 and plutonium.

Dozens of vehicles lie abandoned and covered in overgrown bushes along what was once a stretch of road near the power plantNo deaths were caused by the events or short term radiation exposure but it is thought people in the area worst hit will have a slightly higher risk of developing certain cancers in the future. Now 5 years on there is still a 12.5 km is still in place with thousands of people still exiled from their homes. The wild has reclaimed the land making it look like a scene from an apocalyptic film.

It could be centuries before the area is truly deemed safe to live on again.

Pre-Warning; This has happened before

Japan is no stranger to tsunamis; the 1896 and 1933 Sanriku earthquakes (Mg 8.5 and 8.4 respectively) also brought deadly waves. For this reason tsunami barriers have been constructed both on and off shore, trees were planted along the coastline, vertical evacuation buildings were built to the highest standards and regular evacuation training was introduced. But none of these were built to with stand the sheer force of a tsunami of this magnitude.

In 2001 a team from Tohoku University published an article in Journal of Natural Disaster predicting such an event occurring every 800-1100 years. Within the Sendai Plain there is evidence of at least 3 major tsunami deposits all left within the past 3000 years. On July 9th 869 BC what is believed to be a magnitude 8-9 earthquake occurred off the coast of Sanriku causing a major tsunami which left deposits up to 4 km inland. So given that we knew an event like this had occurred before, why was Japan not better prepared for March 11th?

Sadly human nature does not always listen to the reason of science. It is often easier to believe ‘it won’t happen in my life time’ and then brush the threat under the carpet for future generations. The problem is it does not matter how much we study the mechanics of our planet we are still no where near being able to predict these disasters with any degree of accuracy meaning preparation is our best defence.

Aftermath

A report issued by the Japanese government in May 2015 claimed the events of March 11th 2011 caused $300 billion dollars. A confirmed 15,894 people lost their lives, 2,562 people are still unaccounted for.

5 years on the area is yet to recover. An estimated 174,000 are still displaced mainly due to the exclusion zone still heavily in place around the Fukushima plant. Soon as the initial rescue operation was completed the Tohoku Earthquake Tsunami Joint Survey Group was assembled. A team of natural scientists and engineers from 63 universities world wide set out to understand what made this tsunami so powerful and how we can protect our selves from further events. By the end of 2011 the Japanese government had passed laws to establish “tsunami-safe cities” and pledged billions of dollars to an intense 5 year clean up operation. It was clearly a bigger job than they originally thought….

Today there are still over 60,000 people living in temporary accommodation.For residents once living near the Fukushima power plant they will probably never return to there own homes. Sendai is still trying to recover from the tragic events but also now living in fear that this could occur again.

It is for this reason I choose to go in to studying geoscience. We all live at the mercy of our planet and most of us never even consider the risk the land beneath our feet poses. Prediction, preparation and knowledge can save lives and this is what I one day want to help with.

 

Figure 1; http://www.dailymail.co.uk/news/article-1365318/Japan-earthquake-tsunami-The-moment-mother-nature-engulfed-nation.html

Figure 2; http://earthquake.usgs.gov/earthquakes/shakemap/global/shake/c0001xgp/

Figure 3; http://minookatap.com/2011/08/22/japan-book-club-the-big-wave-5/

Figure 4; http://www.livescience.com/39110-japan-2011-earthquake-tsunami-facts.html

Figure 5; https://7plaguesofgod.wordpress.com/2011-tsunami-japan/

Figure6; http://vassarchronicle.com/section/politics/foreign-affairs/lack-of-regulation-fukushima-meltdown/

Figure 7; http://www.dailymail.co.uk/news/article-3263714/Destroyed-man-reclaimed-nature-Amazing-images-reveal-exclusion-zone-Fukushima-abandoned-overgrown-wilderness.html

 

 

 

Today in Geological History; Feb 19th – Huaynaputina 1600

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Today 416 years ago South America experienced its most explosive eruption in historical times. The unassuming Huaynaputina volcano sits in southern Peru just 26 km of Ubinas, the countries most active volcano. Unlike its 5672 m neighbour, Huaynaputina has no distinct topographic elevation and lays inside a 2.5 km crater leading many to believe it was just a mountain caused by other forces. Laying in the Andean Volcanic Belt where the Nazca Plate subducts under the western edge of the South American Plate it is situated on the rim of the Rio Tambo canyon further camouflaging it to the untrained eye.

The sleeping giants last eruption was in February 1600. Reaching an impressive VEI 6, it was the biggest eruption of the past 2000 years.

Details of the eruption were captured beautifully by Fray Antonio Vazquez de Espinosa a Spanish monk travelling through Central and South America at the time. Days before the eruption booming noises were heard from the vicinity and steam was seen seeping from the volcano. Locals began to panic, preparing young girls for sacrifice to appease Supay the god of death who people believed was angry at them and causing the mountains behaviour. February 15th marked a strong increase in activity with tremors becoming stronger and more frequent, many began to leave the area fearing something bigger was coming.

At roughly 5 P.M. on February 19th, Huaynaputina erupted violently catapulting ash high in to the stratosphere. Pyroclastic flows sped down all sides of the volcano, to the south mixing with the waters of the Rio Tambo river causing devastating lahars.  Within just 24 hours, Arequipa was covered with 25 centimetres (10 in) of ash. Ashfall was reported 250–500 kilometres (160–310 mi) away, throughout southern Peru and in what is now northern Chile and western Bolivia. It is thought that more than 1500 people were killed by the eruption its self although with little record of populations at the time the figure varies between sources. 10 villages were completely buried by ash and regional agricultural economies took 150 years to recover fully.

It was not just South America which was effected by the eruption. Ice cores recorded a spike in acidity at the time indicating a phenomenal amount of sulphur dioxide was released. Effects on the climate right around the Northern Hemisphere (Southern Hemispheric records are less complete), leading to 1601 being the coldest year in six centuries, leading to one of the worst famines ever recorded in Russia. In Estonia, Switzerland and Latvia, there were bitterly cold winters in 1600–1602 leading the deaths of hundreds; in 1601 in France, the wine harvest came late and in Germany production of wine collapsed completely. In Japan, Lake Suwa had one of its earliest freezings in 500 years and even China recorded peach trees blooming late.

An eruption of this scale in the populated Peru would be devastating so close watch is kept on Huaynaputina and its more active neighbours.

 

Figure 1; https://commons.wikimedia.org/wiki/File:Huaynaputina.jpg

Figure 2; https://volcanohotspot.wordpress.com/2015/04/12/volcanoes-of-peru-3-huaynaputina-catastrophe-in-1600/