Friday 28 February 2014

Yorkshire families forced to evacuate home by sinkhole.

Three homes were evacuated after a 7.5 m wide sinkhole oppened up in Rippon, North Yorkshire, on Monday 16 February 2014. Two homes have subsequently been re-occupied, but one home remains empty, having apparently suffered significant damage due to the hole. Nobody was hurt in the incident, although the familly dog needed to be rescued by the Fire Brigade.

A hundred-year-old detatched house in Rippon, North Yorkshire, which suffered structural damage after a sinkhole opened up on 16 February 2013. Press Association.

Sinkholes are generally caused by water eroding soft limestone or unconsolidated deposits from beneath, causing a hole that works its way upwards and eventually opening spectacularly at the surface. Where there are unconsolidated deposits at the surface they can infill from the sides, apparently swallowing objects at the surface, including people, without trace.

According to the British Geological Survey the area around Rippon is particularly vulnerable to sinkholes, due to Permian gypsum deposits, which lie close to the surface, and which are readily soluble when rainwater filters through to them. The UK has suffered a series of sinkhole-related incidents this winter, due to exceptionallty high rainfall, which has caused a number of flooding related and geological problems accross the country.

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Australian town still blanketed in smoke three weeks after fire started at coalmine.

The town of Morwell roughly 100 km to the east of Melbourne in southern Victoria, Australia, is still blanketed in smoke three weeks after a fire was deliberately started at the GDF Suez Australian Energy operated Hazelwood Coal Mine, which lies to the south of the town. The fire was started on an area of the open pit mine, which is used to supply a power station at the same site, no longer under active excavation, which was apparently covered by soil and grass as part of an ongoing remediation plan.

Fire blazing on a coalface at the Hazelwood Coal Mine. Kieth Pakenham/County Fire Authority. 

Authorities in Victoria have not ordered a mandatory evacuation of the town, as carbon monoxide levels are not considered high enough, but have recommended that vulnerable people, such as the elderly, young children, pregnant women and anyone with pre-existing lung conditions, temporarily re-locate, and have distributed 25 000 face masks to concerned citizens.

Environmental groups in the area have called on the state government to do more, with the Victorian Greens calling for an organised evacuation of vulnerable persons and the Environmental Defenders Office calling for a full public enquiry into the incident. Local residents are said to be planning a demonstration, and considering a class law suit due to the disruption to business and health risks caused by the fire.

The Victoria Police have reported finding signs of an earlier attempt to start a fire at the site, probably dating from late January, suggesting that the fire started on 9 February was both deliberate and pre-meditated, rather than an accidental or opportunistic act.

February is generally the hottest and driest month of the year in Victoria, making fighting the fire particularly difficult, and raising the possibility of it triggering bush fires. The mine and surrounding area have further been affected by a series of large cracks which have opened up in the ground, suggesting that coal seems are burning beneath the surface. These have led to road closures, and further raise the risk of the fire spreading to new areas.

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Phreatic eruption on Mount Poás.

The  Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional in Costa Rica reported a large phreatic eruption on Mount Poás, a volcano in the central part of the country, slightly after noon local time (slightly after 6.00 pm GMT) on Tuesday 25 February 2014. Phreatic eruptions occur when magma or other very hot material is produced by a volcano in direct contact with water, in this case beneath the surface of a crater lake, causing a large volume of the water to convert immediately to vapor, resulting in an explosion. On this occasion the eruption resulted in a blast which through material over 300 m into the air.

Phreatic eruption on Mount Poás on Tuesday 25 February 2014. Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional.

Mount Poás rises to 2708 m above sea level, but has gently sloping, forested flanks making the summit easily accessible. The summit consists of two craters, each with a lake. To the south is the cool, clear, Lake Botos, which has not seen an eruption for 7500 years, and to the north is Laguna Caliente, which is thermally heated, extremely acidic (about pH 0), and prone to frequent eruptions. The volcano and its surrounding area form the Poás Volcano National Park.

Costa Rica, along with the rest of Central America, likes on the southwest margin of the Caribbean Plate. To the south the Cocos Plate is being subducted along the Middle American Trench, passing under Central America as it sinks into the Earth. As this happens it is heated by the friction and the warmth of the planet's interior, causing it to partially melt. Some of the melted material then rises through the overlying Caribbean Plate, fuelling the volcanoes of Central America.
See also Magnitude 6.0 Earthquake off the coast of northwest Costa Rica, Eruption on Mount Turrialba, Costa Rica, Eruption on Mount Poás, Costa Rica and Substantial Earthquake in Costa Rica.  

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Thursday 27 February 2014

Three new species of Vetigastropod Snails from the Plio-Pliestocene of The Philippines.

Vetigastropods are considered to be the most ancient, and primative, group of Snails. They are exclusively marine, but found in almost all marine environments, from the intertidal zones to the deepest abysal depths. Vetigastropods have nacrous (mother of pearl) shells, made from layers of aragonite platelets connected by protein fibres. This is thought to be the earliest form of shell to have appeared in Molluscs, with many groups of Molluscs separately evolving more durable solid calcite shells. Many Vetigastrolpods also retain breathing holes in their shells separate to the appatures from which the body extends, another trait considered to be primative in Gastropods (i.e. a trait seen in the earliest memers of the group, and subsequently lost in most members). Keyhole Limpets, Abalones, Top Shells and Turban Snails are Vetigastropods.

In a paper published in the journal Zootaxa on 21 January 2014, Renate Helwerda and Frank Wesselingh of the Naturalis Bidiversity Center in Leiden, The Netherlands, and Suzanne Williams of The Natural History Museum in London descibe three new species of fossil Vetigastropod Snail from the Plio-Pliestocene Santa Cruz Formation on Cabarruyan (or Anda) Island  in the and around Tiep on neighbouring Luzon Island in the Philippines, as part of a wider study into Vetigastropod fossils at the area.

Map showing the locations on Cabarruyan where the majority of the specimens were obtained. Hewlwerda et al. (2014).
The first new species described is placed in the genus Halystina (a genus of small deepwater Snails known from the Pacific around the Philippines and New Caladonia), and given the specific name conoidea, meaning conical. Halystina conoidea is a 2.1 mm high, 1.7 mm wide Snail, with a ribbed shell, described from 34 specimens from Cabarruyan Island and one from Luzon.

Halystina conoidea, (13) specimen in (a) rear view, (b) apertural view, (c) side view, (d) basal view, (e) apical view, and (14) second specimen in (a) rear view, (b) apertural view, (c) side view, (d) basal view, (e) apical view. Helwerda et al. (2014).

The second new species described is placed in the genus Calliotropis (small to mediume sized marine Snails, found globally and typically in deep waters, and given the specific name arenosa, meaning 'sediment covered'. Calliotropis arenosa has a 3.4 mm by 2.7 mm conical shell, ribbed and sediment covered; this sediment covering is considered to be an adaptation of the species rather than a preservational feature, as it is present in all discovered specimens (175, all from Cabbaruyan), all of which are covered by a layter of sediment of even thickness. Furthermore the apatures of the shells are not filled with sediment, which would be expected if the covering were a result of preservational artifact.

Calliotropis arenosa in (a) rear view, (b) apertural view, (c) basal view, (d) apical view. Helwerda et al. (2012).

The fthird new species described is placed in the genus Ethminolia (a genus of large Top Shells currently found in the waters around Australia and Tasmania) and given the specific name wareni, Anders Warén of the Swedish Museum of Natural History, a noted deepwater malacologist. Ethminolia wareni is described from 310 specimens recovered from 14 different sites on Anda Island. It has a flattened conical shell, 3.0 mm high by 4.4 mm wide, weekly ribed and with brown blotches and a nacrous shine.

Ethminolia wareni in (50)(a) rear view, (b)apertural view, (c) basal view, (d) apical view. (51)(a)rear view, (b) apertural view, (c) basal view, (d) apical view. (52) SEM detail of protoconch. Helwerda et al. (2014). 

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Tuesday 25 February 2014

Two children killed by landslide in the French Maratime Alps.

Two children aged 7 and 11 were killed when a rock measuring approximately 5 m by 10 m fell rom an overhanging cliff onto a holiday challet where they were staying during a landslide at Isola in the Maratime Alps at about 5.00 am local time (4.00 am GMT) on Sunday 23 February 2014. Five adults from two families who were also staying at the chalet escaped with minor injuries, and were treated in hospital in Nice, 70 km to the south. The names of the affected families have not yet been released, but it is understood that the chalet was part of a British-built resort largely used by families from the UK.

 Rescue workers at the remains of the Isola Chalet on Sunday 23 February 2013. The Independent.

The incident happened after after a period of extended rain, combined with a sudden thaw in the area, which is primarily a ski resort at this time of year. Landslides are a common problem after severe weather events, as excess pore water pressure can overcome cohesion in soil and sediments, allowing them to flow like liquids. Approximately 90% of all landslides are caused by heavy rainfall. When this is combined with a sudden thaw this can result in additional problems. As well as contributing additional water to any flooding, the thawing often affects ice in cracks in rock faces, which may have been weakened by the epansion of the water as it initially froze (ice occupies more space than an equivalent mass of water, due to its crystaline structre), but which have remained in place due to the adhesive properties of the ice, often resulting in quite large rockfalls.

Isola suffered a large rockfall in 2009, which trapped a large number of people, including many British tourists, when it burried a road connecting the chalet resort to the rest of the village. In January 2014, 2 people were killed when a rockfall struck a train in the Maratime Alps.

See also Over 100 people forced from homes by landslide in Dundee, Scotland, Magnitude 5.4 Earthquake off the coast of El Hierro, At least six dead as Atlantic Storm hits Britain and France, Supermarket destroyed by Italian landslide and Five dead and one missing as western Europe is hit by worst Atlantic Storm in a decade.

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GJ 504b, a cold Jovian exoplanet in a wide orbit about a Sun-like star.

In the past two decades a large number of planets have been discovered orbiting other stars (exoplanets). The vast majority of these have been large planets orbiting close to their host stars, such planets being easier to detect due to the influence that their gravity has on the star. Planets further from their stars are harder to detect, as their gravity has less effect upon the star, and they have long orbital periods which will tend to mask this anyway. Such planets are more likely to be detected by direct imaging, though this will require separate observations over a long period of time to confirm the relationship with the host star.

In a paper published on the online arXiv database at the Cornell University Library on 12 August 2013 and in The Astrophysical Journal on 1 September 2013, a team of scientists led by Masayuki Kuzuhara of the Department of Earth and Planetary Science at The University of Tokyo and the National Astronomical Observatory of Japan and the Department of Earth and Planetary Sciences at the Tokyo Institute of Technology describe the detection of a superjovian planet orbiting the Sun-like star GJ 504 at a distance of 43.5 AU (i.e. 43.5 times the distance between the Earth and the Sun).

GJ 504 (or Gliese 504 or 59 Virginis) is 57 light years from Earth in the constellation of Virgo. It is a G-type Yelow Dwarf Star estimated to have 1.22 times the mass of the Sun, and to be about 160 million years old.Kuzahara et al. observed this star using the Subaru Telescope operated by the National Astronimical Observatory of Japan on Mauna Kea, Hawaii, between 26 March 2011 and 25 May 2012.

These observations enabled them to detect a smaller object close to the star, and establish that it is in fact gravitationally bound (orbiting) the larger body. The planet is named GJ 504b (Gliese 504b), making the parent body GJ 504A (when naming bodies in stellar systems other than our own, stars are indicated with an upper case letter and planets with a lower case letter.

Image of GJ 504A and GJ 504b produced by the Subaru 8.2 m telescope on Mauna Kea. Kazahara et al. (2013).

GJ 504b is thought to have a mass approximatelly four times that of Jupiter, making it the largest planet discovered by direct imaging (larger planets have previously been discovered by the influence of their gravity on their parent stars, but these have all been to close to their stars for direct imaging), and to orbit the star GJ 504A at a distance of 43.5 AU, making it amoungst the fursthest planets from its parent star yet discovered. The planet is thought to have an effective surface temperature of 510 k (237°C), making it the coolest superjovian lanet yet discovered.

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