Asteroid 2015 TA206 passes the Earth.

Asteroid 2015 TA206 passed by the Earth at a distance of 18 560 000 km (48.3 times the average distance between the Earth and the Moon, or 12.4% of the average distance between the Earth and the Sun), slightly after 4.20 pm GMT on Friday 23 October 2015. There was no danger of the asteroid hitting us, though had it done so it would have presented a genuine threat. 2015 TA206 has an estimated equivalent diameter of 36-110 m (i.e. a spherical body with the same mass would be 36-110 m in diameter), and an object towards the upper end of this range would pass through the atmosphere and directly impact the ground with a force of about 45 megatons (about 2650 times the explosive energy of the Hiroshima bomb), causing devastation over a wide area and creating a crater about 1.5 km across, and resulting in global climatic problems that could last for years or even decades.

The calculated orbit of 2015 TA206. JPL Small Body Database.

2015 TA206 was discovered on 13 October 2015 (ten days before its closest approach to the Earth) by the European Space Agency's Optical Ground Station on Tenerife in the Canary Islands. The designation 2015 TA206 implies that it was the 5151st asteroid (asteroid A206) discovered in the first half of October  2015 (period 2015 T).

2015 TA206 has an 1726 day orbital period and an eccentric orbit tilted at an angle of 9.84° to the plane of the Solar System that takes it from 1.09 AU from the Sun (i.e. 109 % of the average distance at which the Earth orbits the Sun) to 4.54 AU from the Sun (i.e. 454% of the average distance at which the Earth orbits the Sun, over three times the distance at which the planet Mars orbits and close to the orbit of Jupiter). It is therefore classed as an Amor Group Asteroid (an asteroid which comes close to the Earth, but which is always outside the Earth's orbit). 

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Asteroid 2015 TG144 passes the Earth.

Asteroid 2015 TG144 passed by the Earth at a distance of 5 109 000 km (13.3 times the average distance between the Earth and the Moon, or 3.42% of the average distance between the Earth and the Sun), slightly before 9.00 am on Friday 16 October...

Asteroid TC179 passes the Earth.

Asteroid 2015 TC179 passed by the Earth at a distance of 4 733 000 km (12.3 times the average distance between the Earth and the Moon, or 3.16% of the average distance between the Earth and the Sun), slightly after 8.15 pm on Wednesday 14 October...

Asteroid 2015 TB25 passes the Earth.

Asteroid 2015 TB25 passed by the Earth at a distance of 3 658 000 km (9.51 times the average distance between the Earth and the Moon, or 2.45% of the average distance between the Earth and the Sun), slightly before 7.55 pm GMT on Sunday 11 October...

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'Mysterious' crack on Wyoming hillside linked to slow-moving landslip.

A group of hunters in Washakie County in northern Wyoming reported finding an apparently mysterious crack on the side of a hill in the Bighorn Mountains on Friday 23 October 2015. The crack is roughly 750 m in length, and 50 m wide at its widest, and is located about 16 km to the south of the town of Tensleep. This initially caused some alarm in the area, due to the proximity to the Yellowstone Caldera, a vast hotspot volcano that covers an area of roughly 55 by 75 km which last erupted about 70 000 and which has been suggested as a potential future hazard to settlement over a wide area of the central United States.

Large crack which appeared on the side of a hill in Washakie County, Wyoming. SNS Outfitter & Guides.

However the Wyoming State Geological Survey have suggested that the crack is more likely to be the result of a slow moving landslide, with one section of rock and soil moving slowly away from another, creating a visible crack at the surface, and have warned the public to stay away from the area as it may present a hazard to health. An underground spring is thought to have provided moisture which fueled this event, running over a layer of hard rock, through a more porous, weakly consolidated layer above. Such underground streams can lead to landslips when the pressure of pore water overcomes the cohesion of the sediment, allowing the wet layer to flow like a liquid, effectively becoming a lubricant for the movement of overlying deposits. Such events are more common in Wyoming in the spring, when rainfall is higher, but can happen at any time of year.

Detail of the rack which appeared on the side of a hill in Washakie County, Wyoming. Randy Becker.

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House destroyed by landslide in Salt Lake City.

A luxury house has been destroyed by a landslide and several neighbouring properties have had to be evacuated following a landslide on a housing...

Magnitude 3.4 Earthquake in the Yellowstone National Park, northwest Wyoming.

The United States Geological Survey recorded a Magnitude 3.4 Earthquake at a depth of 9.2 km in the Yellowstone National Park in northwest Wyoming...

Worker killed at North Antelope Rochelle Mine, Wyoming.

A worker has been killed at the Peabody Energy operated North Antelope Rochelle Minein Campbell County, Wyoming, on Wednesday 4 June 2014. The incident happened at about 6.00 a, when...

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Hurricane Patricia: The most severe storm ever recorded causes widespread flooding but relatively few casualties.

Hurricane Patricia formed as a tropical depression over the eastern Pacific Basin in mid-October 2015, before increasing rapidly in intensity on 22 October, increasing to an Category 5 hurricane (a hurricane with sustained winds of more than 252 kilometers per hour) within 24 hours. On 23 October the storm was recorded as having sustained winds of 325 kilometers per hour and a low pressure of 879 millibars shortly before making landfall in Jalisco State, Mexico, on 23 October. This was the fastest drop in pressure and growth in wind-speed ever recorded for a tropical storm, and matched the highest sustained wind speed ever recorded for such a storm, set by Typhoon Nancy in 1961 (a record thought likely to be inaccurate as the methods used to record wind-speeds in the early 1960s tended to produce over-estimations). 

 Animation of Hurricane Patricia making landfall on the southern coast of Mexico on 23 October 2015, based upon images from the GOES-15 Satellite. Rosenstiel School of Marine and Atmospheric Science/University of Miami/National Oceanic and Atmospheric Administration.

  

The extreme severity of Hurricane Patricia prompted authorities in Mexico to evacuate around 50 000 people from coastal areas in Colima, Jalisco, and Nayarit states. Fortunately the hurricane dropped in intensity as rapidly as it grew, and while still a Category 5 storm when it made landfall (the first Category 5 storm ever to make landfall on the southern coast of Mexico), it has dropped back to a tropical depression (storm with sustained winds of less than 61 kilometers per hour) within 24 hours of making landfall.

 Damage caused by Hurricane Patricia at Chamela in Jalisco State, Mexico. AP.

The hurricane made landfall in an area of Jalisco with a low population density, which combined with the program of evacuations has been credited with a very low loss of life for a storm of this size. Six fatalities were reported in the state, two people killed by a falling tree and four more in an automobile accident associated with the storm. However damage caused by the storm was still severe with over 9000 homes destroyed, including the entire town of Chamela, and extensive damage to crops across much of the state.

Damage caused by Hurricane Patricia in Barra de Navidad in Jalisco State, Mexico. Omar Torres/AFP/Getty Images.

In neighbourig Colima State around 400 homes were destroyed, and severe damage has been recorded to infrastructure, with damage recorded to schools, medical centers and roads, as well as flooding again causing extensive damage to crops and agricultural land. Extensive crop damages were also recorded in Michoacán and Nyarit states, while Quintana Roo state received a record breaking 502 mm of rain within 24 hours and suffering extensive flood damage, particularly in the city of Chetumal, where about 1500 homes were affected. Flooding was also recorded in Veracruz, Tabasco, Oaxaca, Chiapas, Guerrero and Tapachula States.

A banana plantation destroyed by Hurricane Patricia in Colima State, Mexico. Getty Images.

In Central America flooding was recorded in Guatemala, El Salvador, Honduras and Nicaragua, with numerous landslides, and extensive damage to homes and crops. Four people died in flooding in El Salvador and one in Guatemala, while in Nicaragua one person was killed and three injured in a landslide at a mine.

 Flooding in El Progreso, Honduras. Bomberos de Honduras.

In the United States flooding caused by Hurricane Patricia affected many parts of southern Texas, causing severe disruption around Houston. In Navarro County in the north of the State a flash flood washed away rail tracks causing a freight train to derail, though fortunately nobody was hurt in the incident. Heavy rains associated with the remnants of the storm caused a levee to breach south of New Orleans in Louisiana, and caused disruption up the east coast of North America as far as Quebec, where power outages were attributed to the effects of the storm.

Train derailment in Navarro County, Texas, caused by Hurricane Patricia. KGO-TV.

Tropical storms are caused by the warming effect of the Sun over tropical seas. As the air warms it expands, causing a drop in air pressure, and rises, causing air from outside the area to rush in to replace it. If this happens over a sufficiently wide area then the inrushing winds will be affected by centrifugal forces caused by the Earth's rotation (the Coriolis effect). This means that winds will be deflected clockwise in the northern hemisphere and anti-clockwise in the southern hemisphere, eventually creating a large, rotating Tropical Storm. They have different names in different parts of the world, with those in the northwest Atlantic being referred to as hurricanes.

 Photograph of Hurricane Patricia crossing the Mexican coast taken from the International Space Station. Scott Kelly/NASA.

Despite the obvious danger of winds of this speed, which can physically blow people, and other large objects, away as well as damaging buildings and uprooting trees, the real danger from these storms comes from the flooding they bring. Each drop millibar drop in air-pressure leads to an approximate 1 cm rise in sea level, with big tropical storms capable of causing a storm serge of several meters. This is always accompanied by heavy rainfall, since warm air over the ocean leads to evaporation of sea water, which is then carried with the storm. These combined often lead to catastrophic flooding in areas hit by tropical storms.

 Vehicle swept from a road during a flash flood in Texas associated with Hurricane Patricia. International Business Times.

It has been suggested that the exceptional severity of Hurricane Patricia may be the beginning of a much wetter climate phase associated with this years El Niño weather system over the southern Pacific Ocean, a phenomenon that typically brings high levels of rainfall to the southwest United States, though if this is the case then the weather has arrived dramatically early, as the increase in storm activity associated with El Niño does not usually begin in the Americas until December.

 Hotel rooms exposed after Hurricane Patricia ripped the roof off the building in Morelos State, Mexico. Rebecca Blackwell/AP.

The El Niño is the warm phase of a long-term climatic oscillation affecting the southern Pacific, which can influence the climate around the world. The onset of El Niño conditions is marked by a sharp rise in temperature and pressure over the southern Indian Ocean, which then moves eastward over the southern Pacific. This pulls rainfall with it, leading to higher rainfall over the Pacific and lower rainfall over South Asia. This reduced rainfall during the already hot and dry summer leads to soaring temperatures in southern Asia, followed by a rise in rainfall that often causes flooding in the Americas and sometimes Africa. Worryingly climatic predictions for the next century suggest that global warming could lead to more frequent and severe El Niño conditions, extreme weather conditions a common occurrence.

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Two people killed as Hurricane Barbara makes landfall on Mexican south coast.         Hurricane Barbara made landfall on the southern coast of Oaxaca State in Mexico at around noon local time on Wednesday 29 May 2013, with sustained wind...

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Symphysanodon andersoni: A second specimen of the Bucktoothed Slopefish from the south coast of Oman.

Slopefish, Symphysanodontidae, are deepwate Perciform Fish known from the Atlantic, Indian and Pacific Oceans. Like many deepwater orgnanisms the biology and diversity of the group is poorly understood, with most species being known from only a very few number of specimens captured in deep sea trawls. To date only twelve species have been described, all of which are placed in a single genus, Symphysanodon, with another undescribed species known from a single specimen recovered from the stomach of a Coelacanth captured in the Comoros Islands. The Bucktoothed Slopefish, Symphysanodon andersoni, is known only from a single specimen caught at a depth of 190-290 m to the southwest of the Socotra Islands in the Guf of Aden in 1974 (three further specimens assigned to this species reported from the Gulf of Kutch, an inlet in the northeastern quadrant of the Arabian Sea on the west coast of India in 2003 have now been re-assigned to another species).

In a paper published in the journal Zootaxa on 28 September 2015, William Anderson of the Grice Marine Biological Laboratory at the College of Charleston, Mikhail Chesalin of the Fisheries Research Center-Salalah of the Ministry of Agriculture and Fisheries Wealth of the Sultanate of Oman, Laith Jawad of Flat Bush, New Zealand and Said Al Shajibi, also of the Fisheries Research Center-Salalah of the Ministry of Agriculture and Fisheries Wealth of the Sultanate of Oman, describe a second specimen of Symphysanodon andersoni from a Fish trap at a depth of about 80 m off Raysut Port on the south cast of Oman.

This specimen is identified as belonging to the same species as the original by the number of tubed scales along the lateral line, which is larger in this species than in other members of the genus, plus the number of gillrakers and depth of the body at the origin of the dorsal fin. It is 204 mm in length, larger than the original specimen (157 mm), and a dark orange-red in colour.

Freshly collected specimen of Symphysanodon andersoni caught in a fish trap off the south coast of Oman. Mikhail Chesalin in Anderson et al. (2015).

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Philometrid Nematodes from Perciform Fish off the north Australian coast.                   Philometrids are large Nematodes parasitizing Fish . They show a high degree of sexual dimorphism, with males typically only a few mm in length, while...

A new species of Serranine Perchlet from the Philippines.                                                   The Philippines form a major component of the...

A new species of Rabbitfish from southern India, Sri Lanka and the Maldives.           Rabbitfish (Siganidae) are morphologically conservative Perciforme Fish found on Coral reefs in the Indo-Pacific Region. They get their name from their prominent...

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Hundreds known to have died following massive deep Earthquake in northeast Afghanistan.

Four hundred and forty people are known to have died and thousands more are missing or injured following a massive deep Earthquake in Badakhshan Province in north-eastern Afghanistan on Monday 26 October 2015. The quake was measured as having a Magnitude of 7.5 and occurring at a depth of 712 km by the  United States Geological Survey and was felt as far away as Tashkent in Uzbekistan, New Delhi in India and Kathmandu in Nepal, as well as in parts of Tajikistan, Kyrgyzstan and Xinjiang Province, China. The initial event has been followed by a large number of aftershocks, many in excess of Magnitude 4.0.

Earthquake damage Takhar Province, Afghanistan on 27 October 2015. AP.

Despite the Earthquake having happened in northeastern Afghanistan, the majority of the fatalities are thought to have occurred in northern Pakistan, where the event triggered a series of landslides. Damage and casualties far away from the epicenter (point on the ground directly above the point of maximum movement) are common for massive deep Earthquakes, where the energy can be spread over a very wide area before it reaches the surface. On this occasion northern Pakistan is thought to have been particularly vulnerable due to a record-breaking storm in the area the day before the event, which brought 136 mm of rain to the city of Islamabad within 24 hours, more than twice the previous record for any 24 hours in the city, 49.4 mm. 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. Fatalities have also been reported in Jammu and Kashmir State, India.

Damage in Mingora in the Swat District of Khyber-Pakhtunkhwa Province of Pakistan following the 26 October 2015 Earthquake. Hazrat Bacha/Reuters.

Eastern Afghanistan lies close to the boundary between the Indian and Eurasian tectonic plates, which runs through northern Afghanistan. The Indian Plate is moving northward relative to the Eurasian Plate, causing folding and uplift along this boundary, which has led to the formation of the Hindu Kush Mountains of Afghanistan, the Himalayas and the other mountain ranges of Central Asia., and which makes the nations in this boundary zone prone to Earthquakes.

Plate boundaries and movements beneath southern Pakistan, Iran and the Arabian Sea. University of Southampton.

Afghanistan is one of the poorest nations on Earth and has suffered decades of war. This means that few (if any) buildings in the country are protected against the effects of Earthquakes, with many buildings in the area made of mud brick, a building material considered particularly hazardous during quakes, as the bricks have a tendency to liquify, trapping and suffocating people inside. The poor state of the transport network within the country and low numbers of medical staff mean that people injured in quakes are more likely to die as a result of their injuries than in more developed nations, adding to the death toll during such events.

The approximate location of the 26 October 2015 Badakshan Earthquake.Google Maps.

Witness accounts of Earthquakes can help geologists to understand these events, and the structures that cause them. The international non-profit organization Earthquake Report is interested in hearing from people who may have felt this event; if you felt this quake then you can report it to Earthquake Report here.

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Thirteen confirmed deaths in Karachi landslide.

At least thirteen people have died following a landslide in the Gulistan Johar District of Karachi, the capital of Sindh Province in Pakistan, early on Tuesday 13...

Death toll thought to have exceeded 800 as heat wave hits Sindh Province, Pakistan.

The death toll from a heat wave hitting Sindh Province in Pakistan is thought to have exceeded 800. A total of 775 deaths had been...

Afghanistan landslide kills at least 52.

Fifty two people have been confirmed dead after a landslide struck a remote village in the Khawahan District in Badakhshan Province in northeastern Afghanistan, close to the border with Tajikistan, early...

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Turtle eggs from the Late Cretaceous of Madagascar.

Turtles are unique among living Amniotes (Vertebrates that can lay eggs out of water, or that give birth to live young and are thought to be descended from ancestors which could lay eggs out of water, i.e. Reptiles, Birds and Mammals) in that they produce eggs with shells of aragonite rather than calcite. As aragonite is less chemically stable than calcite Turtle eggs have lower preservational potential than other Amniote eggs and are therefore less abundant in the fossil record (this lower chemical stability is not likely to be an issue over the lifetime of the egg). Nevertheless fossil Turtle eggs have been found on every continent except Antarctica, where the absence of known fossils is quite likely to be due to the low levels of collecting rather than an absence of specimens

In a paper published in the Journal of Vertebrate Paleontology on 7 August 2015, Daniel Lawver of the Department of Earth Sciences at Montana StateUniversity, Armand Rasoamiaramanana of the Départementde Paléontologie at the Université d’Antananarivo and Ingmar Werneburg of the PaláontologischesInstitut und Museum der Universitát Zürich, the Museum fürNaturkunde at the Leibniz Institut fürEvolutions und Biodiversitátsforschung and the Institut fürBiologie at the Humboldt-Universitãtzu Berlin describe a clutch of Turtle eggs from the Late Cretaceous Morondava Basin of western Madagascar.

The clutch comprises three spherical eggs, one of which retains traces of eggshell. The eggs lacking shells measure 35.5 and 34.8 mm in diameter, the egg with a shell also measures 35.5 mm in diameter. None of the eggs contains any trace of an embryo, suggesting that they were either infertile or did not develop to the point where biomineralization of the skeleton began to occur. The preserved shell is 440 µm thick and is comprised of tightly packed mineral elements indicative of a rigid shell. In areas where the shell has broken away the underlying surface shows numerous small circular features 259-300 µm in diameter made up of crystals radiating from a central point. Such features are typical of Turtle eggs, where aragonite crystals are formed radiating around an organic nucleation point.

Fossil Turtle egg. (A) Whole egg with eggshell preserved on approximately half of the specimen; (B) close-up of underlying sediment with impression of shell units. Scale bars equal 1 cm (A) and 1 mm (B). Lawver et al. (2015).

The nature of the Turtle that laid the Malagasy eggs is unclear. The eggs were found in deposits interpreted as having been deposited close to the shore, raising the possibility they could have been laid by a Marine Turtle; however the origin of true Marine Turtles remains controversial, and it is not universally accepted that they existed when the eggs were buried. Fossil Turtles are known from the End Cretaceous of Madagascar, but these are younger than the eggs, and all known specimens are Cryptodires (Side-necked Turtles) a non-Marine group known only from the Southern Henisphere. Most modern Turtles, including all Sea Turtles, lay semi-rigid, spherical eggs, while one group, the Kinosternids (Musk Turtles and Mud Turtles) lay rigid, elongate eggs. The Malagasy eggs were clearly rigid-shelled and spherical in shape, a pattern not found in any modern group. This could be seen as a potential ancestral state for Turtle eggs, but semi-rigid spherical Turtle eggs have been found from the Middle Jurassic of England, suggesting that this form had already appeared long before the Malagasy eggs were laid. This suggests that the eggs were laid by a member of an extinct Turtle lineage, though how closely related this animal was to modern Turtles is obscure.

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Pappochelys rosinae: A Proto-Turtle from the Middle Triassic of Badem Württemberg, Germany.                                                       Turtles have a fairly good fossil record, as would...

Desmatochelys padillai: A Protostegid Turtle from the Early Cretaceous of Colombia.        The Protostegid Turtles were a group of Turtles known from the Cretaceous that are thought to have been members of the Chelonioidea, the group that includes the two living Marine Turtle groups, the Chelonidoidea (Sea Turtles) and Dermochelyidae (Leatherback...

Calcified Lizard eggs with preserved embryos from the Early Cretaceous of Thailand.      Among living Vertebrate groups, Lizards show the most diverse range of reproductive strategies, with species known that reproduce sexually and parthanogenically  (check spelling – a form of asexual reproduction in which the female fertilizes her own eggs, rather...

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Evacuations after sinkhole swallows houses in Itogon Municipality, the Philippines.

Around 70 people have been evacuated from their homes after a large sinkhole opened up in the Virac District of Itogon Municipality on Luzon Island, the Philippines on Thursday 22 October 2015, swallowing several houses. All of the evacuated persons are from homes directly affected by the incident or close to it, but there fears that the sinkhole may grow, affecting as many as 500 houses in the densely populated area. Despite the alarming nature of the incident there are no reports of any injuries associated with this event.

Aerial photograph of the Itogon Municipality sinkhole. Office of Civil Defense-Cordillera Administrative Region.

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. Potash, a potassium salt, is readily soluble and can be dissolved quickly if water gains access to deposits, leading to the rapid formation of sinkholes.

The approximate location of the Itogon Municipality sinkhole. Google Maps.

The Itogon Municipality sinkhole is thought to be directly above a tunnel that forms part of a former gold mine. The area is economically dependent on gold mining and many former mine tunnels underly the area, causing fears that a tunnel mat have collapsed in the aftermath of Typhoon Koppu, which brought the heaviest rainfall experienced in the area for a decade on Sunday-Monday this week, causing widespread flooding, and potentially weakening mineworkings and unstable sediments. The incident is being investigated by the Mines and Geosciences Bureau.

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Magnitude 5.8 Earthquake under southwestern Luzon Island, the Philippines.

The United States Geological Survey recorded a Magnitude 5.8 Earthquake at a depth of 106 km beneath southwestern Luzon Island in the Philippines, at about 9.50 pm local time (about 1.50...

Typhoon Koppu kills at least 20, caused widespread devastation on Luzon Island.

Typhoon Koppu has killed at least 20 people in a series of devastating floods and landslides on northern Luzon Island in the Philippines, causing extensive damage to many homes and businesses and, in particular to...

Eruptions on Mount Bulusan.

Mount Bulusan, a 1565 m stratovolcano (cone shaped volcano made up of layers of ash and lava) on the southern tip of the Bicol Peninsula on Luzon Island, in the Philippines, began erupting slightly after 9.45 am local time on Friday 1 May 2015, with a small...

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