Wednesday, July 17, 2013

GLOBAL VOLCANISM: Lava Flow, Ash And Gas Emissions Intensifies At Ecuador's Mount Reventador!

July 17, 2013 - ECUADOR - Scientists say lava flow and ash and gas emissions have intensified at a second Ecuadorean volcano, Reventador, as the full-bore eruption of the Tungurahua cone continues.




Ecuador's Geophysics Institute says the lava flow on Reventador's southern flank has increased since Saturday but poses no immediate threat to villagers in the region 60 miles (100) kilometers) east of the capital, Quito.

The 11,400-foot (3,475-meter) volcano is nearly three times that distance from Tungurahua to the southwest.

It has been roaring since Sunday, when 200 people were evacuated from its flanks and one pyroclastic blast was heard as far away as the coastal city of Guayaquil.


A man walks on rocks and ashes spewed by the Tungurahua volcano in the outskirts of the village of Cusua, Tungurahua province, Ecuador, Sunday July 14, 2013. Ecuador has issued an orange alert, the second-highest warning level, for towns near the volcano as its level of activity rose and at least 200 people were evacuated from the area, civil defense authorities said.(AP Photo/Dolores Ochoa)

Tungurahua is 16,480 feet (5,023 meters) high and has been active since 1999.

Reventador had its last big eruption in November 2002. - AP.




PLANETARY TREMORS: Massive Portuguese Earthquake "Could Send A Three-Metre High Tsunami Towards British Coast And Submerge Isles Of Scilly" - Disaster Planners Say Repeat Of 1755 Great Lisbon Quake Is Overdue!

July 17, 2013 - BRITAIN - Swathes of Britain could be left totally underwater by a tsunami in the Atlantic Ocean, it has been claimed.

An earthquake off Portugal could trigger disastrous levels of flooding along the coast of the UK, scientists have said.


The Isles of Scilly, which include Tresco, pictured, lie 45 miles off the coast of Cornwall, coulde be wiped out by a tsunami if Portugal suffered another devastating earthquake.

The Isles of Scilly and parts of Cornwall would be worst hit if there were a repeat of the Lisbon earthquake of 1755.

Experts believe that a quake similar to the devastating one 250 years ago would send a 10ft wall of water towards the UK.

The tsunami would crash over the tip of Cornwall within a few hours – leaving much of the coast underwater and wiping the tiny Scilly Isles off the map.

The prospect of the natural disaster was raised at a meeting of the Devon and  Cornwall Local Resilience Forum, which includes police, town planners and emergency services.

Members of the LRF told the meeting they fear Britain could suffer its own version of the 2004 Boxing Day Tsunami. They want an early warning system to alert bathers and people living on the coast, similar to technology used across Asia and America.


St Martin's is one of the five inhabited Isles of Scilly - plus dozens of islets - with a total population of around 2,100 .

Paul Netherton, assistant chief constable of Devon and Cornwall Police and LRF chairman, said other countries have suffered by failing to plan ahead.

He told the forum: ‘After seeing the devastation in Japan and Thailand we have to ask the question of the scientific community – what and where would be the impact, is it likely and, if it is, should we plan for it?

A lot of areas would cope but in others it would cause a big problem. We have to consider whether we do anything differently than we do now for severe weather events.

‘Tsunami are different – you don’t know they are coming and the water keeps coming and coming.’

Britain was last hit by a tsunami in 1755, the year of the great Lisbon earthquake, the meeting in Bristol was told.

In the event of an earthquake in the Atlantic, the public would currently rely on the British Geological Survey to register the quake and the arrival of a subsequent wave at nearby Portugal.

Neil Hamlyn, LRF coordinator in Devon and Cornwall, said: ‘The Isles of Scilly could be affected greatly, the islands could be covered and disappear.’


Quake zone: Lisbon was ripped open by the 1755 earthquake which left fissures 15 feet wide in the city centre.

The 1755 Lisbon earthquake almost totally destroyed Lisbon and adjoining areas and had a magnitude in the range of 8.5 on the Richter scale.

Under the Civil Contingencies Act of 2004, the UK maintains a National Risk Register of Civil Emergencies.

The very high risk table is currently topped by pandemic flu, terrorist attacks and coastal flooding, though the last major civil flooding emergency was on the east coast in 1953.

Mr Hamlyn says a tsunami is in the top 20 of the second category of high risks.

Other uniquely regional threats include a nuclear submarine incident at Devonport dockyard and possible contamination from old tin mines in Cornwall.

Work has also already been done to predict the catastrophic impact should a massive slab of rock twice the volume of the Isle of Man break away from the island of La Palma, in the Canary Islands, and smash into the Atlantic Ocean.

The resulting tsunami, higher than Nelson’s Column and faster than a jet aircraft, would devastate the eastern seaboard of America and inundate much of southern Britain.


THE GREAT LISBON EARTHQUAKE - ONE OF THE DEADLIEST IN HISTORY
The 1755 Lisbon earthquake, also known as the Great Lisbon Earthquake, occurred on Saturday, November 1, 1755.

The earthquake, which had its epicentre around 200 miles south-west of Cape St Vincent on the Portuguese coast, almost totally destroyed Lisbon and had a magnitude in the range of 8.5 on the Richter scale.

It struck in the morning and lasted between three and six minutes, leaving vast cracks 15ft wide in the city centre streets.

Around 40 minutes later, a vast tsunami engulfed the city's docks and centre, followed by two more waves.

Estimates place the death toll in Lisbon alone between 10,000 and 100,000 people, making it one of the deadliest earthquakes in history.

But its devastating impact was not only felt in Portugal - it travelled more than a 1,000 miles before crashing into the British Isles.

An engraving by Laplante from Le Monde Illustre shows how Lisbon was destroyed in the earthquake of 1755.

At around 2pm on the same day, a wave reported to be between three to four metres in height hit the shores of Cornwall, smashing into Mount's Bay, the area's highest point, where it killed at least one person.

The waves (there were two more) also struck the south coast and were even seen in the River Thames in London.

The tsunami even reached as far as Galway in Ireland, where it was described as being two metres high.

French writer Arnold Boscowitz claimed the wave caused a 'great loss of life and property occurred upon the coasts of Cornwall'.


Estimates suggest that the death toll in Lisbon reached between 10,000 and 100,000 people, making it one of the deadliest earthquakes in history.

Recent studies show that should another earthquake of the same magnitude happen, it could affect the south west of England.

A wave would take approximately five hours to travel to Britain, with maximum water heights reaching one to two metres around the vast coast of Cornwall.

But it would peak at around four metres (13ft) in Mount's Bay. - Daily Mail.





PLANETARY TREMORS: 6.0 Magnitude Earthquake Jolts Southern Peru - Prompts Terremoto Aftershocks!

July 17, 2013 - PERU - A 6.0 Peru earthquake 2013 struck yesterday. But another Peru terremoto struck moments ago today July 17, 2013 as temblor aftershocks hit throughout the country.


USGS earthquake location.


Officials tell news that a 4.6 magnitude Peru aftershock began moments ago. On Tuesday, a series of comparable magnitude quakes struck across the nation. Then late in the day, outside of Chivay, a 6.0 Peru earthquake struck.

The 6.0 Peru earthquake began just after 9:31 pm local time, officials tell news. The quake had virtually no depth. It started only four miles below ground level. Reps tell news that the quake was eleven miles west of Chivay and fifty-five miles northwest of Arequipa. The quake was also ninety-two miles northeast of Camana and ninety-four miles west of Ayaviri. The quake began roughly two hundred fifty miles west of La Paz.


USGS earthquake shakemap intensity.


The latest quake started minutes ago. A 4.6 magnitude quake began west of Tabalosos, at a different epicenter. The quake was deep as well. It began at 7:59 AM local time at started thirty-seven miles below ground level. The quake was twelve miles west of Lanas and twenty-seven miles south of Moyobamba. Reps tell news that the quake was thirty-one miles east of Sirtor and roughly four hundred miles north of Lima. Damage assessment is pending. - LA Late.


Tectonic Summary - Seismotectonics of South America (Nazca Plate Region)
The South American arc extends over 7,000 km, from the Chilean margin triple junction offshore of southern Chile to its intersection with the Panama fracture zone, offshore of the southern coast of Panama in Central America. It marks the plate boundary between the subducting Nazca plate and the South America plate, where the oceanic crust and lithosphere of the Nazca plate begin their descent into the mantle beneath South America. The convergence associated with this subduction process is responsible for the uplift of the Andes Mountains, and for the active volcanic chain present along much of this deformation front. Relative to a fixed South America plate, the Nazca plate moves slightly north of eastwards at a rate varying from approximately 80 mm/yr in the south to approximately 65 mm/yr in the north. Although the rate of subduction varies little along the entire arc, there are complex changes in the geologic processes along the subduction zone that dramatically influence volcanic activity, crustal deformation, earthquake generation and occurrence all along the western edge of South America.

Most of the large earthquakes in South America are constrained to shallow depths of 0 to 70 km resulting from both crustal and interplate deformation. Crustal earthquakes result from deformation and mountain building in the overriding South America plate and generate earthquakes as deep as approximately 50 km. Interplate earthquakes occur due to slip along the dipping interface between the Nazca and the South American plates. Interplate earthquakes in this region are frequent and often large, and occur between the depths of approximately 10 and 60 km. Since 1900, numerous magnitude 8 or larger earthquakes have occurred on this subduction zone interface that were followed by devastating tsunamis, including the 1960 M9.5 earthquake in southern Chile, the largest instrumentally recorded earthquake in the world. Other notable shallow tsunami-generating earthquakes include the 1906 M8.5 earthquake near Esmeraldas, Ecuador, the 1922 M8.5 earthquake near Coquimbo, Chile, the 2001 M8.4 Arequipa, Peru earthquake, the 2007 M8.0 earthquake near Pisco, Peru, and the 2010 M8.8 Maule, Chile earthquake located just north of the 1960 event.


USGS plate tectonics for the region.



Large intermediate-depth earthquakes (those occurring between depths of approximately 70 and 300 km) are relatively limited in size and spatial extent in South America, and occur within the Nazca plate as a result of internal deformation within the subducting plate. These earthquakes generally cluster beneath northern Chile and southwestern Bolivia, and to a lesser extent beneath northern Peru and southern Ecuador, with depths between 110 and 130 km. Most of these earthquakes occur adjacent to the bend in the coastline between Peru and Chile. The most recent large intermediate-depth earthquake in this region was the 2005 M7.8 Tarapaca, Chile earthquake.

Earthquakes can also be generated to depths greater than 600 km as a result of continued internal deformation of the subducting Nazca plate. Deep-focus earthquakes in South America are not observed from a depth range of approximately 300 to 500 km. Instead, deep earthquakes in this region occur at depths of 500 to 650 km and are concentrated into two zones: one that runs beneath the Peru-Brazil border and another that extends from central Bolivia to central Argentina. These earthquakes generally do not exhibit large magnitudes. An exception to this was the 1994 Bolivian earthquake in northwestern Bolivia. This M8.2 earthquake occurred at a depth of 631 km, making it the largest deep-focus earthquake instrumentally recorded, and was felt widely throughout South and North America.

Subduction of the Nazca plate is geometrically complex and impacts the geology and seismicity of the western edge of South America. The intermediate-depth regions of the subducting Nazca plate can be segmented into five sections based on their angle of subduction beneath the South America plate. Three segments are characterized by steeply dipping subduction; the other two by near-horizontal subduction. The Nazca plate beneath northern Ecuador, southern Peru to northern Chile, and southern Chile descend into the mantle at angles of 25° to 30°. In contrast, the slab beneath southern Ecuador to central Peru, and under central Chile, is subducting at a shallow angle of approximately 10° or less. In these regions of “flat-slab” subduction, the Nazca plate moves horizontally for several hundred kilometers before continuing its descent into the mantle, and is shadowed by an extended zone of crustal seismicity in the overlying South America plate. Although the South America plate exhibits a chain of active volcanism resulting from the subduction and partial melting of the Nazca oceanic lithosphere along most of the arc, these regions of inferred shallow subduction correlate with an absence of volcanic activity. - USGS.




GLOBAL VOLCANISM: Underground Magma Accumulation - Researchers Say Japan's Mount Fuji May Erupt If Earthquake Causes Cracks In The Volcano!

July 17, 2013 - JAPAN - Researchers at the National Institute of Advanced Industrial Science and Technology (AIST) say that Mount Fuji may erupt if a future massive earthquake will cause its insides to crack. The last time that the 3,776-metre volcano erupted was in 1707, in what is now known as the Hoei eruption.




The scientists warned that another eruption is imminent because underground magma has been accumulating inside the volcano for 300 years now.

They came to this conclusion by observing the number of craters in the mountain through aerial photos and on-site investigations. They also analysed reports from the past eruptions between 10,000 years ago and that last eruption.

The study showed that there were a lot of dikes created before 1707 and that prevented the magma from rising. But two magnitude earthquakes struck between 1703 and 1707, which caused the magma to rise to the surface.

They expect that magma has accumulated under the ground due to low-frequency earthquakes that have been recorded under the mountain.

In case a large-scale quake occurs, like the predicted Nankai Trough earthquake in the next few years, Mount Fuji will most likely erupt, according to volcanologist and AIST researcher Akira Takada.

The explosion will most likely affect two of Japan’s major islands – Honshu and Shikoku. Mount Fuji was recently named a World Heritage site by UNESCO and is one of the most prominent symbols of Japan’s culture. - Japan Daily Press.




PLANETARY TREMORS: Strong Magnitude 6.0 Earthquake Strikes Papua New Guinea!

July 17, 2013 - PAPUA NEW GUINEA - An earthquake measuring 6.0 on the Richter scale jolted Bougainville region, Papua New Guinea at 09:35:54 GMT on Tuesday, the U.S. Geological Survey said.


USGS earthquake location.

The quake had a depth of 44.3 kilometres (27 miles) and was initially determined to be at 6.3085 degrees south latitude and 154.7822 degrees east longitude.

The epicentre was 77 kilometres (48 miles) west of Panguna, Papua New Guinea; 84 kilometres (52 miles) west of Arawa, Papua New Guinea and 666 kilometres (414 miles) northwest of Honiara, Solomon Islands.


USGS earthquake shakemap intensity.


Tectonic Summary - Seismotectonics of the New Guinea Region and Vicinity
The Australia-Pacific plate boundary is over 4000 km long on the northern margin, from the Sunda (Java) trench in the west to the Solomon Islands in the east. The eastern section is over 2300 km long, extending west from northeast of the Australian continent and the Coral Sea until it intersects the east coast of Papua New Guinea. The boundary is dominated by the general northward subduction of the Australia plate.

Along the South Solomon trench, the Australia plate converges with the Pacific plate at a rate of approximately 95 mm/yr towards the east-northeast. Seismicity along the trench is dominantly related to subduction tectonics and large earthquakes are common: there have been 13 M7.5+ earthquakes recorded since 1900. On April 1, 2007, a M8.1 interplate megathrust earthquake occurred at the western end of the trench, generating a tsunami and killing at least 40 people. This was the third M8.1 megathrust event associated with this subduction zone in the past century; the other two occurred in 1939 and 1977.

Further east at the New Britain trench, the relative motions of several microplates surrounding the Australia-Pacific boundary, including north-south oriented seafloor spreading in the Woodlark Basin south of the Solomon Islands, maintain the general northward subduction of Australia-affiliated lithosphere beneath Pacific-affiliated lithosphere. Most of the large and great earthquakes east of New Guinea are related to this subduction; such earthquakes are particularly concentrated at the cusp of the trench south of New Ireland. 33 M7.5+ earthquakes have been recorded since 1900, including three shallow thrust fault M8.1 events in 1906, 1919, and 2007.


USGS plate tectonics for the region.


The western end of the Australia-Pacific plate boundary is perhaps the most complex portion of this boundary, extending 2000 km from Indonesia and the Banda Sea to eastern New Guinea. The boundary is dominantly convergent along an arc-continent collision segment spanning the width of New Guinea, but the regions near the edges of the impinging Australia continental margin also include relatively short segments of extensional, strike-slip and convergent deformation. The dominant convergence is accommodated by shortening and uplift across a 250-350 km-wide band of northern New Guinea, as well as by slow southward-verging subduction of the Pacific plate north of New Guinea at the New Guinea trench. Here, the Australia-Pacific plate relative velocity is approximately 110 mm/yr towards the northeast, leading to the 2-8 mm/yr uplift of the New Guinea Highlands.

Whereas the northern band of deformation is relatively diffuse east of the Indonesia-Papua New Guinea border, in western New Guinea there are at least two small (magnitude less than 100,000 km²) blocks of relatively undeformed lithosphere. The westernmost of these is the Birds Head Peninsula microplate in Indonesia's West Papua province, bounded on the south by the Seram trench. The Seram trench was originally interpreted as an extreme bend in the Sunda subduction zone, but is now thought to represent a southward-verging subduction zone between Birds Head and the Banda Sea.

There have been 22 M7.5+ earthquakes recorded in the New Guinea region since 1900. The dominant earthquake mechanisms are thrust and strike slip, associated with the arc-continent collision and the relative motions between numerous local microplates. The largest earthquake in the region was a M8.2 shallow thrust fault event in the northern Papua province of Indonesia that killed 166 people in 1996.

The western portion of the northern Australia plate boundary extends approximately 4800 km from New Guinea to Sumatra and primarily separates Australia from the Eurasia plate, including the Sunda block. This portion is dominantly convergent and includes subduction at the Sunda (Java) trench, and a young arc-continent collision.

In the east, this boundary extends from the Kai Islands to Sumba along the Timor trough, offset from the Sunda trench by 250 km south of Sumba. Contrary to earlier tectonic models in which this trough was interpreted as a subduction feature continuous with the Sunda subduction zone, it is now thought to represent a subsiding deformational feature related to the collision of the Australia plate continental margin and the volcanic arc of the Eurasia plate, initiating in the last 5-8 Myr. Before collision began, the Sunda subduction zone extended eastward to at least the Kai Islands, evidenced by the presence of a northward-dipping zone of seismicity beneath Timor Leste. A more detailed examination of the seismic zone along it's eastern segment reveals a gap in intermediate depth seismicity under Timor and seismic mechanisms that indicate an eastward propagating tear in the descending slab as the negatively buoyant oceanic lithosphere detaches from positively buoyant continental lithosphere. On the surface, GPS measurements indicate that the region around Timor is currently no longer connected to the Eurasia plate, but instead is moving at nearly the same velocity as the Australia plate, another consequence of collision.

Large earthquakes in eastern Indonesia occur frequently but interplate megathrust events related to subduction are rare; this is likely due to the disconnection of the descending oceanic slab from the continental margin. There have been 9 M7.5+ earthquakes recorded from the Kai Islands to Sumba since 1900. The largest was the great Banda Sea earthquake of 1938 (M8.5) an intermediate depth thrust faulting event that did not cause significant loss of life. - USGS.