Wednesday, 31 July 2013

The perihelion of Comet 103P/Hartley 2.

Comet 103P/Hartley 2 is a Jupiter Family Comet (a comet with a period of less than 20 years with an orbit angled at less than 30° to the plane of the Solar System) with an orbit that it completes every 6.46 years, and which takes it from an aphelion (furthest point from the Sun) of 5.87 AU (i.e. 5.87 times as far from the Sun as the Earth, just outside the orbit of Jupiter) in to a perihelion of 1.05 AU (just outside the orbit of the Earth. The comet was by the Deep Impact Spacecraft, which came within 694 km of on November 4, 2010. This revealed the comet to have an unexpected 'peanut' shape with a distinct waist, and two distinct and separate sources of emissions, with a carbon dioxide rich jet being produced from the sunlit part of the comet, and a water-rich jet being emitted from the waist region, behavior which was quite unexpected.

Image of Comet 103P/Hartley 2, captured by the Deep Impact Spacecraft. NASA.

In a paper published on the online arXiv database at Cornell University Library on 20 May 2013, Zhong-Yi Lin of the Institute of Astronomy at the National Central University in Jhongli City, Taiwan, Luisa Lara of the Instituto de Astrof and Wing-Huen Ip, also of the Institute of Astronomy at the National Central University present the results of a study of Comet 103P/Hartley 2 made over the months April to December 2010, during which period the comet reached its perihelion (in late October), and therefore could be expected to produce the greatest amount of emissions, using data from the Centro Astron (CAHA) at Calar Alto, the Lulin Observatory operated by the Institute of Astronomy and the Xinglong Station of the National Astronomical Observatory in Beijing.

Like the Deep Impact Spacecraft, Lin et al. were able to observe two distinct jet features emitting from Comet 103P/Hartley 2, one of which pointed away from the Sun, the other towards it. Carbon dioxide and cyanide were detected in both jets, at a fairly typical ratio for comets of this type. The sunward jet was first observed in late September, and persisted into November. The sunward jet appeared more intense than the outward jet, but this may have been because it was also directed towards the Earth. The comet also produced significant quantities of dust, which appeared redder in the inward jet and bluer in the outward jet; this did not vary as the comet approached perihelion.

(Top) Image of comet 103P/Hartley 2 obtained on October 11, 2010 with R broadband filter, with a contour plot added to show light intensity. (Bottom) The same image with an azimuthal
median pro file added; the image is centered on the nucleus, the arrows point out the jets, T labels the tail, and the streaks are trailed stars. Lin et al. (2013).

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Shooting at Lonmin's Marikana Platinum Mine.

A 49 year old man, believed to be a team leader for the Association of Mineworkers and Construction Union (AMCU), was shot dead at the  Lonmin-owned Marikana Platinum Mine in Rustenburg in northeast South Africa. The incident happened on Sunday 28 July 2013, but the South African Police Service have yet to release details of the event, which is thought to be associated with the ongoing (and often bloody) dispute between the AMCU and it's more established rival the National Union of Mineworkers (NUM).

The approximate location of the Lonmin Marikana Mine. Google Maps.

The NUM is closely associated with the ruling ANC, and was heavily involved in the struggle against apartheid. However since the ANC came to power it has been accused of becoming to close to the mining companies, who the ANC need to remain on good terms with. The newer AMCU claim that workers in the mining industry are receiving considerably lower wages than they ought to be able to expect, and have organized a string of strikes across the sector, brining a number of mining companies to the negotiating table, but also resulting in some violent clashes with the police and members of other political organizations. In August 2012 police opened fire on AMCU workers at a rally at the Marikana Mine, killing at least 34 people, the worst single outbreak of violence in South Africa since the end of the Apartheid system.

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Worker killed by landslide at Mingora in the Swat Valley.

A worker with the Water Resources & Power Development Authority was killed by a rock from a landslide while installing an electricity pole in the Gumbad Maira area of Mingora City in the Swat Valley of northwest Pakistan on Monday 29 July 2013. The man has been named as Fazal Akbar, a senior linesman with the authority, from Bara Bandai. He was taken to the Saidu Teaching Hospital but declared dead on arrival. 

Fazal Akbar, a senior linesman with the Water Resources & Power Development Authority, who was killed by a rockfall on Monday 29 July 2013. Zama Swat.

The Swat Valley, along with other areas of northern Pakistan, has suffered a series of flash floods, and landslides, which have destroyed a number of homes as well as uprooting many electricity poles in the area, leading to a running battle by workers to keep power supplies running. There has been rainfall in the area, but the flood events are largely associated with melting snow and glaciers higher in the mountains, a problem that is becoming worse due to rising global temperatures. 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.

The approximate location of the 29 July 2013 Mingora landslide. Google Maps.

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Tuesday, 30 July 2013

Earthquake on the Morvern Peninsula.

The British Geological Survey recorded a Magnitude 1.8 Earthquake at a depth of 5 km on the Morvern Peninsula in west coast of Scotland slightly after 11.05 British Summertime (slightly after 10.05 GMT) on Tuesday 30 July 2013. This is a small quake, highly unlikely to have caused any damage or injuries, but may have been felt locally. 

The approximate location of the 30 July 2013 Morvern Peninsula Earthquake. Google Maps.

Earthquakes become more common as you travel north and west in Great Britain, with the west coast of Scotland being the most quake-prone part of the island and the northwest of Wales being more prone  to quakes than the rest of Wales or most of England.

The precise cause of Earthquakes in the UK can be hard to determine; the country is not close to any obvious single cause of such activity such as a plate margin, but is subject to tectonic pressures from several different sources, with most quakes probably being the result of the interplay between these forces.

Britain is being pushed to the east by the expansion of the Atlantic Ocean and to the north by the impact of Africa into Europe from the south. It is also affected by lesser areas of tectonic spreading beneath the North Sea, Rhine Valley and Bay of Biscay. Finally the country is subject to glacial rebound; until about 10 000 years ago much of the north of the country was covered by a thick layer of glacial ice (this is believed to have been thickest on the west coast of Scotland), pushing the rocks of the British lithosphere down into the underlying mantle. This ice is now gone, and the rocks are springing (slowly) back into their original position, causing the occasional Earthquake in the process. 

Witness accounts of Earthquakes can help geologists to understand these events, and the structures that cause them. If you felt this quake, or were in the area but did not (which is also useful information) then you can report it to the British Geological Survey here.

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African Barrick Gold sued over deaths at Tanzanian mine.

The mining company African Barrick Gold, a subsidiary of the Canadian Barrick Gold Corp, is being sued by representatives of 12 Tanzanian villagers over a series of violent incidents at the North Mara Mine in the Tarime District of the Mara Region of Tanzania, including an incident in May 2011 in which five people were killed and many others injured. The law firm Leigh Day & Co. is arguing in the High Court in London that members of the Tanzanian police, acting as an integrated part of security at the mine, have repeatedly used excessive violence, including shooting at the villagers using tear gas and live ammunition, leading to a total of six deaths and numerous other injuries at the site.

A standoff between mine security guards (blue uniforms) a Tanzanian police officer (green uniform) and a group of villagers at the North Mara Mine on Friday 31 August 2013. Geoffrey York/The Globe and Mail.

African Barrick Gold have stated that it would not compensate the villagers, that it feels the lawsuit to be illegitimate and that it will 'vigorously defend itself against all the claims'. The company argues that the incidents occurred due to police acting in self defense or in the defense of mine employees, after violent intrusions to the site by local villagers. 

The mine operates in an underdeveloped area where artisanal mining is a traditional industry, and while the site is legitimately leased from the Tanzanian government, many local people still regard it, and the gold extracted from it, as being legitimately theirs. It is estimated that around 40 000 people earned their living from artisanal mining at the site prior to Barrick gaining the lease in 2002. Of these around 10 000 have also been displaced from their homes, which were within the area of the concession. These people received only a minimal level of compensation, as the land was deemed to belong to the government.

This has led to an ongoing confrontation between the mine owners and the local population, who feel they have a right to collect gold ore from the site, something Barrick regards as stealing. This has led to a series of violent incidents in which large numbers of people have invaded the site, not just removing gold but also damaging equipment belonging to the company. 

The location of the North Mara Mine. Google Maps.

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Two women killed by landslide in Chittagong, Bangladesh.

Two women were killed in the Lalkhan Bazar area of Chittagong City, Bangladesh, when a 6 m chunk of soil fell onto their home between 4.00 and 5.00 am local time on Sunday 28 July 2013 (between 10.00 and 11.00 pm on Saturday 27 July, GMT). The two, described as Fatema Begum (38) and her daughter Kusum Akhter (15), migrant workers from Comilla who were employed in the garment-making industry, were dwelling in a tin-roofed hut, one of a 'colony' of 30-35 such huts in an area cleared by cutting into a hillside at 90°, by the colony's landlord, Amir Hossain, a second colony, comprising about 20 homes rented from a traffic policeman, is situated at the top of this cutting.

Neighbours attempting to rescue the victims of the 28 July 2013 Chittagong landslide. Anurup Kanti Das/The Daily Star.

The incident took place following heavy rainfall associated with the monsoon season; 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.

Many cities in Bangladesh have seen an explosion in numbers of migrant workers, attracted by growth in the garment industry, which while notorious for its poor conditions, at least pays cash, a valuable commodity in a country with a population traditionally dependent on subsistence farming, where farmland is increasingly being lost to flood events associated with a warming climate and the population is rising at a rate of 1.6% per year. 

This has fueled an expansion in slum housing, which in the case of Chittagong has led to the expansion of housing into hilly areas vulnerable to landslide events in the monsoon season, where it is estimated that around 5000 families are currently dwelling. Local authorities have tried to relocate some of these vulnerable people to tent dwellings erected on public land, but this often leads to evacuated dwellings being relet to newer migrants.

The approximate location of the 28 July 2013 Chittagong landslide. Google Maps.

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Nodosaurid teeth from the Early Cretaceous of southern England.

The Nodosaurids were a group of Ankylosaurid Dinosaurs that differed from other members of the group in having spines, rather than boney clubs, on the ends of their tails, and additional large spines on their shoulders. Most known Nodosaurids have been discovered in North America, but specimens are known from China, Antarctica and England.

In a provisional paper to be published in the journal Acta Palaeontologica Polonica and available online from 13 March 2013, William Blows of the Department of Applied Biological Sciences at City University London and Kerri Honeysett of Bexhill on Sea in East Sussex describe four Nodosaurid teeth from the Isle of Wight and Bexhill on Sea. 

These are distinctive enough to state that they are from a Nodosaurid, but are not assigned to species level, since none of the Nodosaurid specimens known from England has preserved teeth, making it impossible to assign the teeth with confidence to any previously described species, or to say with confidence that they belong to a new species.

The first specimen comes from a plant dedris bed within the the Sudmore Point Sandstone at Sudmore Point east of Brook Chine on the Isle of Wight. It is Barremian in age (between 125 and 129.4 million years old). The Sudmore Point Sandstone is interpreted as having formed on a flat floodplain, with the debris bed representing a flood event. It contains large amounts of disarticulated plant and animal remains. The tooth is nearly complete, comprising both the crown and root, with a total length of 17 mm, 6 mm of which is the crown. 

The Isle of Wight specimen in (A) labial(?) view, (B) distal view and (C) lingual(?) view. Scale bar is 4 mm. Blows and Honeysett (2013).

The other three teeth come from Ashdown Quarry at Bexhill on Sea, where they were located by David Brockhurst, a noted amateur palaeontologist employed at the quarry. They were located within a conglomerate within the Wadhurst Clay Formation, of Valanginian age, making them between 132.9 and 139.8 million years old. 

The first of these is a 20.5 mm tooth with both crown and root, the crown comprising 7 mm of the total. The second is a partial crown 5 mm in heigh, without any root. The third is a 17 mm tooth of which 5 mm is the crown and the remainder is the root; the crown of this tooth appears somewhat worn down.

The first Bexhill on Sea specimen, complete tooth in (A1) lingual(?) view and  (A2) labial(?) view. Blows and Honeysett (2013).

The second and third Bexhil on Sea specimens. Partial tooth in shown in opposite views (B1 and B2), and complete tooth in (C1) lingual(?) view, (C2) distal view, (C3) labial(?) view. Blows and Honeysett (2013).

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Saturday, 27 July 2013

Four people killed by landslide in North Sulawesi.

At least four people have been killed and a further three are missing following a landslide on the Tongo River in North Sulawesi. The river is currently in flood following exceptional rainfall, which has led to the evacuation of around 600 people from three villages in Gorontalo District. The landslide apparently happened close to Ombulo Hijau village, in Bone Pantai subdistrict, late in the evening of Friday 27 July 2013. All of the victims are said to be from a single family, and two of those known to have died were children, aged seven and ten.

Rescue workers recovering a body from the site of the 27 July 2013 Gorontalo landslide. Press TV.

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.

The approximate location of the 27 July 2013 Gorontalo landslide. Google Maps.

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Two workers killed in landslide at Bihar quarry.

Two workers have been killed and 17 others were buried in a landslide at Parharpur in Bihar State, India. The 17 buried workers were dug out by local villagers, and none are thought to have serious injuries. Northern India has suffered a series of often lethal landslides in recent weeks due to an exceptionally severe monsoon. However in this case local authorities are blaming the event entirely on carelessness by the quarry owners. The Parharpur quarry is legal, and produces high-quality sandstones used in the building industry from a series of large pits dug into the flat alluvial plains of the area. However safety concerns have been raised about the site before, particularly a level of silicosis ('miners-lung'; a build up of quartz particles in the lungs which can eventually prove fatal), considered unacceptably high by NGOs.

The approximate location of the Parharpur quarry. Google Maps.

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A new species of Chrysomeline Leaf Beetle from Ireland, England and Tasmania.

Chrysomeline Leaf Beetles are one of the most diverse and widespread groups of Beetles, with over 35 000 described species from across the globe. They feed on living plant matter, and many species, such as the Colorado Potato Beetle, are significant agricultural pests, either due to direct damage to crops or by acting as vectors for plant diseases.

In a paper published in the journal Zootaxa on 24 June 2013, Chris Reid of the Department of Entomology at the Australian Museum and David de Little of the Rosny Research Facility at the Tasmanian Museum and Art Gallery describe a new species of Chrysomeline Leaf Beetle found infesting Eucalyptus trees in County Kerry, Ireland and across Tasmania as well as in a garden in London.

The new species is placed in the genus Paropsisterna, and given the specific name selmani, in honour of the late Brian Selman of University of Newcastle-on-Tyne, an expert on Australian Chrysomeline Leaf Beetles. Paropsisterna selmani is a 7-9 mm oval Beetle with distinctive but variable colouration. The males tend to be darker and redder than the females, and all the beetles seem to be darker in spring, after emerging from hibernation. The Beetle feeds on the leaves of Eucalyptus and where these trees are grown in large monospecific plantations, appears capable of achieving epidemic proportions capable of causing considerable economic damage quite rapidly. The species appears to be a native of Tasmania which has become established in Ireland and England, and given the popularity of the fast-growing Eucalyptus as a plantation tree around the world, would seem to have to potential to become a significant pest globally.

Paropsisterna selmani from Tasmania in spring. David de Little in Reid & de Little (2013).

Paropsisterna selmani from London in autumn. Paula French in Reid & de Little (2013).

Paropsisterna selmani new adult shortly after emerging from pupae, County Kerry, Ireland. Finbarr Horgan in Reid & de Little (2013).

The larvae of Paropsisterna selmaniReid & de Little (2013).

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Friday, 26 July 2013

Anti-fracking protestors arrested at Sussex demo.

Sixteen protestors have been arrested at a protest against exploratory drilling at Balcombe in West Sussex by Caudrilla Resources, currently the only company involved in hydraulic fracturing (fracking) in the UK. The company was granted a permit to cary out drilling at the site by West Sussex County Council and began operations on Thursday 25 July 2013, leading to protests by around 250 local residents and environmental activists. The protests continued through the night and following day, leading to complaints from Caudrilla that the protestors were inhibiting access to the site and causing alarm to workers. Around a hundred officers from Sussex Police moved in on the protestors at about 3.20 pm on Friday 26 July, arresting sixteen and moving others from the site.

A protestor being arrested at the Balcombe protest. Protestors and local witnesses have stated that none of those arrested resisted the police, which Sussex Police have not contested. Frack Free Sussex

Caudrilla have stated that the operation will involve the drilling of a 914 m well and 762 m horizontal borehole, and will not involve any fracking, which would require additional permission from West Sussex County Council. They have also stated that they are following all regulations put in place by the Department of Energy and Climate Change, the Environment Agency, the Health and Safety Executive and West Sussex County Council.

However protestors have expressed doubts that the group would be drilling exploratory wells without the intention of further operations, and have suggested that the current legal structure around such drilling operations favors wealthy companies over local communities. Many have also complained that the policing operation was disproportionate, and that they are a symptom of the state intervening to protect a 'wealthy few' against a local community standing up for itself.

Sussex Police have stated that they support the right to protest, but also have a duty to facilitate contractors carrying out their business.

The approximate location of the Balcombe drilling site and protests. Google Maps.

Fracking, or Hydraulic Fracturing, is a process by which water, sand and chemicals are forced into buried sediments in order to shock them into releasing trapped hydrocarbons, which can then be extracted for commercial use. This has proved highly controversial with environmentalists, who accuse the process of causing Earthquakes, polluting groundwater, and using large amounts of fresh water. The process uses high pressure blasts in order to produce shock waves, which will hopefully cause the release of hydrocarbons. Shock waves in buried strata are, in layman's terms, Earthquakes, so an increase in Earthquakes in areas where Fracking is being practiced is not surprising. Environmentalists have also raised concerns that making large amounts of new hydrocarbons available will lead to further rises in atmospheric CO₂, with consequences for the global climate.

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At least nine dead following landslide in Gansu Province, northwest China.

At least nine people are known to have died, and another four are missing, after a landslide in Nanyu Village in the Qinzhou District of Gansu Province, in northwest China, that took place at about 9.30 local time (1.30 am GMT) on Thursday 25 July 2013, following heavy rains and flooding. Another four people are still missing following a second landslide in the nearby Yongguang Village. This is the same area that was hit be a series of Earthquakes on Sunday 21 July, causing widespread damage to infrastructure and killing at least 95 people.

The approximate location of the 25 July 2013 Nanyu landslide. Google Maps.

The area of southern Gansu where this occurred has a landscape largely made up of loess hills; which is to say loosely consolidated (but very fertile) fine soils comprised of material blown in from the Gobi Desert, a formerly fertile area that had its rainfall cut off by the impact of India into southern Asia and subsequent rise of the Himalayas. The area is cut through by the Yellow River (Huang He), which is fed by glaciers in the Himalayas, but is highly prone to flash flooding and landslides during the seasonal monsoon (another effect of the Himalayas). 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. The combination of fertile soil, frequent flooding and unstable hillsides has led to the Yellow River also being known as the China's Sorrow and Scourge of the Sons of Han, as historically the area has always had a high population, vulnerable to such events.

A landslide cutting through terraced fields in Minxian County, Gansu, following the Earthquakes of 21 July 2013. Reuters.

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Thursday, 25 July 2013

Astroid 2006 BL8 to pass the Earth at 502 000 km.

On Friday 26 July 2013, at 2.35 am GMT, the asteroid 2006 BL8 will pass the Earth at a distance of 503 000 km, roughly 9.3 time the average distance between the Earth and the Moon. There is no danger of the asteroid hitting the Earth, and even if it did, since it is only 48 m across, it is unlikely that much of it would make it through the atmosphere. 

The orbit's of 2006 BL8 and the inner four planets of the Solar System. Image created using the JPL Small Body Database Browser.

2006 BL8 (the name means the 211th object discovered in the second half of January 2006) is an Apollo Group Asteroid (i.e. one who's orbit crosses that of the Earth) with an orbital period of 434 days, which takes it out from the Sunas far as the orbit of Mars and in nearly to the orbit of Venus, though it is unlikely to interact with either of those planets, as its orbit is oblique to the plain of the Solar System, so that it is above that plain when near to the orbit of Venus and bellow that plain when near the orbit of Mars.

The orbit of 2006 BL8 relative to the plain of the Solar System. Image created using the JPL Small Body Database Browser.

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Burning gas rig off the coast of Louisiana.

An oil and gas rig 95 km off the coast off Louisiana which has been burning for a day has begun to collapse into the Gulf of Mexico. The Walter Oil & Gas owned Hercules 265 jack-up rig (an oil rig that can be towed into position, secure itself to the sea floor and begin drilling) caught fire at about 10.50 pm on Tuesday 23 July 2013, local time (3.50 am on Wednesday 24 July, GMT), when it hit an unforeseen pocket of gas while carrying out preliminary drilling for a well in 47 m of water, leading to a blowout at the well. All 44 crew on board were evacuated safely, and two US Coast Guard fire-fighting vessels dispatched to the scene, but it was not possible to stem the supply of gas to the well, and the heat have melted the beams supporting the main derrick (platform) causing it to collapse, and the fire is ongoing.

The burning Hercules 265 rig starting to collapse into the Gulf of Mexico. US Coast Guard.

It is not thought likely that the incident will lead to a major oil spill, as with the 2010 Deepwater Horizon incident, however neither burning rigs in the Gulf of Mexico nor large escapes of methane (a powerful greenhouse gas) are considered a good thing, and Walter Oil and Gas have been instructed by the U.S. Bureau of Safety and Environmental Enforcement to arrange the drilling of a relief well, to try to divert the gas before it reaches the blown-out well.

The locations of the burning Hercules 265 rig, and of the former Deepwater Horizon. International Business Times.

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Magnitude 4.3 Earthquake hits Kern County, California.

A Magnitude 4.3 Earthquake occurred in Kern County, California, slightly after 9.45 am local time (slightly after 4.45 pm GMT) on Wednesday 24 July 2013, according to the United States Geological Survey. The quake occurred at a depth of 6.6 km, roughly 150 km north of Los Angeles or 75 km west of Bakersfield. The quake is unlikely to have caused any damage or casualties, but was felt as far north as North Fork as far south as Anaheim.

The location of the 24 July 2013 Kern County Earthquake. Google Maps.

California is extremely prone to Earthquakes due to the presence of the San Andreas Fault, a tectonic plate margin that effectively bisects the state. The west of California, including Santa Barbara and Los Angeles, is located on the Pacific Plate, and is moving to the northwest. The east of California, including Fresno and Bakersfield is on the North American Plate, and is moving to the southeast. The plates do not move smoothly past one-another, but constantly stick together then break apart as the pressure builds up. This has led to a network of smaller faults that criss-cross the state, so that Earthquakes can effectively occur anywhere.

Witness accounts of Earthquakes can help geologists to understand these events and the underlying structures that cause them. If you felt this quake (or if you were in the area but did not, which is also useful information) then you can report it to the United States Geological Survey here.

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Wednesday, 24 July 2013

Series of Earthquakes in Gansu Province kills at least 95.

A series of Earthquakes in Gansu Province in northwest China has killed at least 95 people and injured over a thousand more, with an estimated 27 000 people being made homeless. The first quake had a Magnitude of 5.9 and stuck at 7.45 am on Monday 22 July 2013 local time (11.45 pm on Sunday 21 July GMT), at a depth of 9.8 km, 13 km east of the town of Chabu, according to the United States Geological Survey. This was followed by a Magnitude 4.7 quake at a depth of 9.4 km 14 km southwest of Xinsi Zhen slightly before 8.10 am local time (slightly before 0.10 am GMT) and a Magnitude 5.6 quake at a depth of 10.1 km 9 km north of Chabu slightly after 9.10 am local time (slightly after 1.10 am GMT). While none of these are exceptionally large quakes, they appear to have triggered a series of landslides across the mountainous region, as well as the collapse of a large number of buildings.

Rescue workers try to restrain a man who has seen his wife's shoes under a mudslide being cleared in Yongguang Village in Minxian County, Gansu Province. AFP/Getty Images.

Much of western China and neighbouring areas of Central Asia and the Himalayas, is prone to Earthquakes caused by the impact of the Indian Plate into Eurasia from the south. The Indian Plate is moving northwards at a rate of 5 cm per year, causing it to impact into Eurasia, which is also moving northward, but only at a rate of 2 cm per year. When two tectonic plates collide in this way and one or both are oceanic then one will be subducted beneath the other (if one of the plates is continental then the other will be subducted), but if both plates are continental then subduction will not fully occur, but instead the plates will crumple, leading to folding and uplift (and quite a lot of Earthquakes). The collision of the Indian and Eurasian plates has lead to the formation of the Himalayan Mountains, the Tibetan Plateau, and the mountains of southwest China, Central Asia and the Hindu Kush.

The approximate location of the Gansu Earthquakes. Google Maps.

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Tuesday, 16 July 2013

Two workers killed in landslide near Attabad Lake, Gilgit-Baltistan.

Two men working on a road-building project near Attabad Lake in Gilgit-Baltistan in the Pakistan Himalayas have been killed by a landslide, reportedly triggered by blasting of the hillside. One of the victims has been identified as a local man, Zohaib Nazeer, the other is understood to be a Chinese engineer. The two men were working on a project to build a replacement section of the Karakoram Highway connecting Pakistan to China, part of which was submerged by the formation of the Attabad Lake on 4 January 2010, by another massive landslide which blocked the Hunza River. The formation of the lake killed 25 people, submerged 19 km of the Karakoram Highway, displaced 6000 people and cut of supply routes to another 25 000. The loss of the supply route, as well as several villages and a significant amount of farmland on the valley floor, has led to considerable hardship in the Gojal Valley, in turn leading to protests and demands for compensation from the Government of Pakistan.

Villagers from the Gojal Valley surveying the scene of the Attabad landslide on 5 January 2010. Zulfiqar Ali Khan/Pamir Times.

The road building project has suffered a string of such incidents, caused by repeated landslides in the valley. Like other areas of the Himalayas, Gilgit-Baltistan has suffered extensive flooding since June 2013, though this has been caused not so much be heavy-rainfall in the area as by high temperature leading to increased runoff from melting glaciers. 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. In 2010 and 2011 the region also saw extensive flooding due to melting glaciers.

Funeral service for victims of the Attabad landslide on 6 January 2013. Zulfiqar Ali Khan/Pamir Times.

Secondary landslide at Attabad Lake on 22 January 2010. Inayat Ali/Pamir Times.

View of the landslide dam and part of the remains of Attabad Village. 1 February 2010. Zulfiqar Ali Khan/Pamir Times.

Good from China being ferried across Attabad Lake to Pakistan, 11 March 2010. Shabbir Ahmed Mir/AP.

An areal view of the newly formed Attabad Lake in May 2010. Shabbir Hussain Imam/AP.

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Monday, 15 July 2013

Typhoon Soulik kills five people in south China.

Typhoon Soulik, which had already claimed four lives in Taiwan, has killed at least five people in south China after making landfall in Fujian Province on Saturday 13 July 2013, bringing with it winds of up to 220 kph. At least three people have died in Guangdong Province, where rainfall peaked at 292.5 mm and the Hanjiang River reached 43.68 m above flood level (the level at which the river is officially considered to be in flood). At least two more died in Jiangxi Province, where rainfall levels reached 354.3 mm. There have been no recorded fatalities in Fujian, where the typhoon first struck, though the high winds and 10 m waves are understood to have caused considerable damage to property.

The remains of a house destroyed by heavy rains in Liandun Village in Guangdong Province. Lian Zhicheng/Xinhua.

Southourn China is already suffering from widespread flooding, and Soulik has added to this. The low pressure above the storms causes water to rise there by ~1 cm for every millibar drop in pressure, leading to a storm surge that can overwhelm low-lying coastal areas, while at the same time the heat leads to high levels of evaporation from the sea - and subsequently high levels of rainfall. This can cause additional flooding on land, as well as waterlogging soils on slopes leading to landslides. 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.

Tropical storms are caused by solar energy heating the air above the oceans, which causes the air to rise leading to an inrush of air. If this happens over a large enough area the inrushing air will start to circulate, as the rotation of the Earth causes the winds closer to the equator to move eastwards compared to those further away (the Coriolis Effect). This leads to tropical storms rotating clockwise in the southern hemisphere and anticlockwise in the northern hemisphere.

These storms tend to grow in strength as they move across the ocean and lose it as they pass over land (this is not completely true: many tropical storms peter out without reaching land due to wider atmospheric patterns), since the land tends to absorb solar energy while the sea reflects it. They are categorised according to their wind speeds; using sustained wind strength (wind speeds maintained for a minute or more) rather than peak wind strength (the strongest gusts). A Super-Typhoon (or Super-Hurricane, or Super-Cyclone, depending on where these occur in the world), or Category 5 storm, has a sustained wind speed of 251 km/h or higher, a Category 3 Typhoon a sustained wind speed of 178-208 km/h.

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Magnitude 3.4 Earthquake in northern California.

The United States Geological Survey recorded a Magnitude 3.4 Earthquake at a depth of 3.4 km approximately 130 km north of San Francisco and 115 km west of Sacramento at 3.40 pm local time (10.40 pm GMT) on Sunday 14 July 2013. There are not likely to be any damage or casualties from this quake, and there are no reports of anybody having felt it, though it is likely that it was noticeable in the Geysers and Clearlake areas.

The location of the 14 July north California Earthquake. Google Maps.

California is extremely prone to Earthquakes due to the presence of the San Andreas Fault, a tectonic plate margin that effectively bisects the state. The west of California, including Santa Barbara and Los Angeles, is located on the Pacific Plate, and is moving to the northwest. The east of California, including Fresno and Bakersfield is on the North American Plate, and is moving to the southeast. The plates do not move smoothly past one-another, but constantly stick together then break apart as the pressure builds up. This has led to a network of smaller faults that criss-cross the state, so that Earthquakes can effectively occur anywhere.

Witness accounts of Earthquakes can help geologists to understand these events and the underlying structures that cause them. If you felt this quake (or if you were in the area but did not, which is also useful information) then you can report it to the United States Geological Survey here.

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200 people evacuated after eruption on Tungurahua.

Around 200 people have been evacuated from the vicinity of Tungurahua Volcano in Ecuador, following an explosive eruption that took place slightly after 6.45 am local time (11.45 am GMT) on Sunday 14 July 2013, throwing up an ash column that reached an altitude of 5 km. The explosion was felt as far away as the Pacific coast, but there are no reports of any casualties related to the event.

View of the ash column over Tungurahua from Quito, 135 km to the northwest. Vicente Costales/El Comercio.

Mount Tungurahua is a stratovolcano (a 'conventional' cone-shaped volcano, the sort you see in Hollywood movies) located in the Sangay National Park in Ecuador, overlooking the town of Baños de Agua Santa. The town's major industry is tourism, attracting visitors to visit the volcano, the hot springs associated with the volcano, and the Amazon Rainforest.

Tungurahua has been intermittently active since 1999 (prior to which it had been inactive for about 75 years), with major eruptions in August 2006, February 2008, May 2010, December 2010 and April 2011. The 2006 eruption killed seven people; two volcanologists and a local family.

The location of the Tungurahua Volcano. Google Maps.

The current Tungurahua volcano is the third on the site, referred to by volcanologists as Tungurahua III. The first volcano on the site, Tungurahua I, built up and then collapsed some time in the Mid-Pleistocene. This was followed by Tungurahua II, which started to grow about 14 000 years ago, then collapsed about 3000 years ago. The current volcano has been growning since this time, and lies within the caldera of Tungurahua II.

Like all South American volcanoes Tungurahua owes its existence to the subduction of the Nazca Plate (which underlies the southeast Pacific) beneath South America. The Nazca Plate is being pushed from the east and forced down into the Earth's interior beneath South America. As it sinks rocks in the crust melt, and the lighter portions of it rise up through the overlying South American Plate to form volcanoes at the surface. These are dotted throughout the Andes Mountains; a range of mountains that is formed by a mixture of volcanism and crumpling of the South American Plate where is is forced against the Nazca Plate.

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Sunday, 14 July 2013

A fossil Isopod Crustacean from the Early Miocene of the Vienna Basin.

Isopods are one of the most numerous and diverse groups of Crustaceans in modern environments, but while preserved specimens are known from as far back as the Carboniferous, they have a limited presence in the fossil record, largely because their exoskeletons are only very lightly mineralized. They are small, flat, benthic Crustaceans known from marine, freshwater and terrestrial environments, where they are known as Woodlice or Pill Bugs, due to the tendency of many species to roll up into tight balls resembling pills for defencive purposes. Most species are detritivores, though some marine forms are parasitic on Fish.

In a paper published in the journal Palaeontology on 7 May 2013, Matúš Hyžný of the Department of Geology and Paleontology at the Faculty of Natural Sciences at Comenius University, Niel Bruce of the Museum of Tropical Queensland at the Queensland Museum and School of Marine and Tropical Biology at James Cook University and the Department of Zoology at the University of Johannesburg and Ján Schlögl, also of Department of Geology and Paleontology at Comenius University, describe a new species of Isopod Crustacean from the Early Miocene of the Vienna Basin.

The new species is placed in the genus Cirolana, and given the specific name feldmanni, in honour of Rodney Feldmann of Kent State University, an expert on fossil Isopods. Cirolana feldmanni is a 1.3-2.0 mm Cirolanid Isopod (detritivorous or parasitic Isopods ranging from 1 mm to 90 cm in length), described from seven specimens found at Cerová-Lieskové in the Vienna Basin in Slovakia.

Cirolana feldmanni. (A) Near-complete specimen. Note that posterior exoskeleton part is preserved in ventral aspect. (B–C) Head region and its interpretive drawing. (D–E) Close-up of the putative basal antennal segments. (F–G) Posterior exoskeleton part in ventral aspect and its interpretive drawing showing preserved pereopod 7. Scale bar represents 1 mm. Hyžný et al. (2013).

Cirolana feldmanni. (A–B) Near-complete specimen. Anterior exoskeleton part is preserved 
as counterpart in (A) and as part in (B), whereas posterior exoskeleton part is preserved vice versa. (C) Interpretive drawing of (B). (D–E) P
repared posterior part with preserved pleotelson and uropods and its interpretive drawing. F, Detail of pleotelson and uropods. Scale 
bar represents 1 mm. 
Hyžný et al. (2013).

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Strange bedfellows in an Early Triassic burrow from the Karoo.

The Early Triassic Karoo Basin contain numerous preserved burrows of small Tetrapods, interpreted as adaptations to a harsh, seasonally dry, climate. These burrows are commonly preserved as casts, formed when the burrow was infilled with sediment different to the surrounding matrix, typically during flood events, and these casts sometimes contain the preserved remains of the animals that lived in the burrows.

In a paper published in the journal PLoS One on 21 June 2013, a team of scientists led by Vincent Fernandez of the Evolutionary Studies Institute at the University of the Witwatersrand describe the results of an examination of one such burrow cast, collected from the lower Lystrosaurus Assemblage Zone on Admiralty Estates at the base of Oliviershoek Pass in KwaZulu Natal Province, South Africa, at the European Synchrotron Radiation Facility, where it was possible to create a three dimensional computer model of the contents of the cast without breaking it open.

The burrow cast contains two preserved animals from completely different groups, a Cynodont ('Mammal-like Reptile'), Thrinaxodon liorhinus, and a Rhinesuchid Amphibian, Broomistega putterilli. Both skeletons are articulated, suggesting that neither was being predated by the other at the time of death (predation generally involves dismembering the prey animal). The Amphibian shows damage to several ribs, as well as a bite mark on the skull, however the ribs show signs of healing prior to death and the bite-make is inconsistent with the dentition of the Cynodont.

Upper-side 3D rendering of the content inside the burrow cast in semi-transparency. Thrinaxodon liorhinus (in brown) is lying on its ventral side; Broomistega putterilli (in grey) deposited upside down on the right side of the Thrinaxodon. Fernandez et al. (2013).

The two animals are preserved in a position that almost suggests they are hugging, but Fernandez et al. suggest this is probably a post-mortem positioning; the burrow filled with water in a flood event drowning the animals, and almost certainly repositioning them, though since the burrow has a narrow entrance it is unlikely that either animal was washed into it. They suggest that the burrow was dug by the Cynodont, as the Amphibian seems poorly adapted to the task and Cynodonts are well documented in similar burrows. They further suggest that the Amphibian entered the burrow after sustaining its injuries, possibly to escape from a predator, and that the Cynodont tolerated this presence, possibly because it was aestivating (dormant, hibernating). This leads them to suggest that the Cynodont may have become dormant during the driest part of the year, and that both animals died as a result of flash flooding at the onset of the rainy season.

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