Friday, July 5, 2013

GLOBAL VOLCANISM: Eruption From Mexico’s Popocatepetl Volcano Grounds United States Flights!

July 05, 2013 - MEXICO - Four U.S. airlines temporarily suspended flights to and from Mexico City on Thursday after a volcano 50 miles from the capital spewed ash, a spokesman for the city’s international airport said.




Three to eight flights on American Airlines, U.S. Airways, Delta Air Lines and Alaska Air Group have been postponed so far, Richard Jimenez, a representative for Mexico City’s international airport told Reuters. “The decision not to fly from Mexico City has been made by these airlines, but the airport is in operable conditions,” Andres Gomez, another airport representative, said on local television.

No Mexican airlines have halted operations, Gomez said. Mexico’s leading airline AeroMexico suspended flights briefly Thursday morning, but resumed operations less than an hour later. The volcano Popocatepetl in the central state of Puebla has been more active this year, prompting officials to raise warning levels but have so far ordered no evacuations.

Officials have kept the volcano’s risk level on hold at “yellow,” the second highest on the four-color spectrum, indicating that there is more activity than usual but no threat of eruption, national emergency services coordinator Luis Felipe said on Twitter.


WATCH: Volcano eruption grounds US and Mexican flights.





On Thursday, ash fell on communities adjacent to the volcano, nicknamed Don Goyo, and reached southern neighborhoods of Mexico City. There is no evidence of volcanic ash in the airport’s immediate vicinity, it announced through its Twitter account.

Volcanic ash can damage jet engines. Mexico City’s airport serves more than 29 million people a year and oversaw 174,511 takeoffs and landings between January and June. - NBC News.





EXTREME WEATHER: Infrastructure And Societal Collapse - Quebec Forest Fire Causes Widespread Blackouts For A Second Day!

July 05, 2013 - CANADA - Half a million Hydro-Québec customers were without power at rush hour for the second straight day, as widespread outages caused by forest fires in northern Quebec affected transmission lines.




The utility said Montreal and other parts of southern Quebec were affected. By 7:30 p.m. most customers had their power restored, and Hydro-Québec tweeted that its three major transmission lines shut down by heat and smoke from forest fires in northern Quebec were operational once again. The blackouts occurred nearly exactly 24 hours after a similar power failure caused by the forest fires, despite the utility’s best efforts to protect the network.

“The re-establishment of the lines was fairly fast,” said Quebec Natural Resources Minister Martine Ouellet in an interview on CBC’s French-language news network RDI. “The heat, the smoke, the particles [from the fire] all interacted with the hydro lines, causing ionization,” Ouellet explained. “That tripped the lines’ safety mechanism. It’s a good thing, as that protected the lines.” She said Hydro-Québec informed her it is spraying other equipment with foam to protect it from the heat of the fires.

The latest blackouts hit several municipalities in Greater Montreal and struck as far away as the Quebec City suburb of Ste-Foy, as well as parts of the Laurentians and the Lanaudière region. The blackouts began at almost precisely the same time as they did yesterday, during the commuter rush hour, affecting traffic lights at many intersections and the lane designation lights on the Champlain Bridge.

Earlier today, Hydro-Québec’s chief executive officer Thierry Vandal said the utility had taken steps to try to ensure there would not be a repeat of yesterday’s outage, which shut down Montreal’s Metro system and affected hospitals and shopping centers. Wednesday’s outage forced the Notre-Dame pavilion of University of Montreal’s hospital network (CHUM) to cancel operations and left people trapped on stalled roller-coasters and other rides at LaRonde, the amusement park on Montreal’s Île Ste-Hélène. - CBC.





PLANETARY TREMORS: Strong 6.1 Magnitude Earthquake Strikes Solomon Islands Region!

July 05, 2013 - SOLOMON ISLANDS - A strong 6.1-magnitude earthquake struck off the Solomon Islands on Friday, the US Geological Survey (USGS) said, but there was no immediate tsunami warning issued.


USGS earthquake location.

The tremor, at a depth of 72 kilometers (45 miles), hit at 4.16am local time (17:16 GMT Thursday) 81km south of the town of Panguna in Papua New Guinea. The USGS issued a “green alert,” to say there was a low likelihood of casualties and damage.

In February the remote town of Lata was hit by a devastating tsunami after an 8.0-magnitude earthquake. The tsunami left at least 10 people dead, destroyed hundreds of homes and left thousands of people homeless. 


USGS earthquake shakemap intensity.


The Solomons are part of the “Ring of Fire,” a zone of tectonic activity around the Pacific that is subject to frequent earthquakes and volcanic eruptions. - Times of India.



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.