Tuesday 30 October 2018

Landslides kill at least nine as Typhoon Yutu passes over Luzon Island, the Philippines.

Four people have died and more than 20 more are trapped after a landslide struck a building that contained offices belonging to the Department of Public Works and Highways in the town of Natonin in Mountain Province on Luzon Island, the Philippines, on Tuesday 30 October 2018. The event occurred amid heavy rains associated with the passage of Typhoon Yutu (referred to as Typhoon Rosita in the Philippines). 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. In a separate incident a father and his three young children were killed in another landslide in the municipality of Banaue, to the south of Natonin, and  a third landslide is reported to have killed a young girl in another province.

The approximate location of the 30 October 2018 Mountain Province landslide. Google Maps.

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 Pacific being referred to as typhoons.

The path and strength of Typhoon Yutu. Thick line indicates the past path of the storm (till 6.00 pm GMT on Monday 30 October 2018), while the thin line indicates the predicted future path of the storm, and the dotted circles the margin of error at 12, 24, 36 and 72 hours ahead. Colour indicated the severity of the storm. Tropical Storm Risk.
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 surge 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.

See also...

Follow Sciency Thoughts on Facebook.

Magnitude 4.9 Earthquake off the southeast coast of Cyprus.

The United States Geological Survey recorded a Magnitude 4.9 Earthquake at a depth of 10 km roughly 40 km off the southeast coast of Cyprus slightly after 2.10 pm local time (slightly after 12.10 pm GMT) on Monday 29 October 2018. There are no reports of any serious damage or injuries from this quake, but it was felt across much of Cyprus.

The approximate location of the 29 October 2018 Cyprus Earthquake. USGS.

The Island of Cyprus overlies the boundary between the Anatolian Plate, which underlies Anatolia, and the African Plate, which underlies most of the Mediterranean. The African Plate is moving northward relative to the Anatolian Plate, and is being subducted beneath it along the Cyprian Trench, which runs to the south of Cyprus. This is not a smooth process, as the plates frequently stick together then break apart once the pressure has built up sufficiently, leading to (fairly frequent) Earthquakes.

To the east the Arabian Plate  is being pushed north and west by the movement of the African Plate, further to the south. This leads to a zone of tectonic activity within the province, as the Arabian and Anatolian plates are pushed together, along the East Anatolian Fault, and past one-another, along the Dead Sea Transform.

 Simplified map of the plate movements of the eastern Mediterranean. Univeriteit Utrecht.
Witness accounts of Earthquakes can help geologists to understand these events, and the structures that cause them. The international non-profit organisation 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.

See also...



Follow Sciency Thoughts on Facebook.

Monday 29 October 2018

Fossil collector injured by landslide at Port Mulgrave, North Yorkshire.

A fossil collector has been injured in a landslide at Port Mulgrave on the North Yorkshire coast on the evening of Saturday 27 October 2018. The victim, described as a man in his 40s, received a broken leg and other injuries when part of the cliff collapsed onto him, burying him up to his waist in mud and rock, but was promptly dug out by local fishermen and kept comfortable until the emergency services arrived, eventually being airlifted to James Cook University Hospital in Middlesbrough. 

 Rescue workers preparing the Port Mulgrave landslide victim to be airlifted to hospital. Staithes Coast Guard.

The incident is the latest in a series of landslips on the North Sea coast of England this autumn, triggered by a long dry summer followed by a wet autumn. In August a woman was injured in a landslip on the Norfolk coast, and a young girl killed in a similar incident at Staithes in North Yorkshire. Since then there have been significant landslides at Saltburn, Cleveland Way and Whitby, all on the same section of coast. Exceptionally dry weather can cause landslides, when exposed soft sediments that usually contain some water drying out and crumbling, undermining anything above, but landslips are most common after wet severe weather events, as excess pore water pressure can overcome cohesion in soil and sediments, allowing them to flow like liquids.

 The cliffs at Port Mulgrove seen from above. UK Fossil Collecting.

The cliffs at Port Mulgrove expose rocks of the Cleveland Ironstone and Whitby Mudstone formations of the Cleveland Basin. These deposits produce both marine and terrestrial fossils of Early Jurassic origin, including numerous Ammonites, Belemnites, and Plants such as Horsetails, as well as less frequent Reptile and Dinosaur remains. Like all erosional coasts, these fossil beds are most productive during bad weather, when frequent landslips on the unstable coastline expose new material. However, this section of coastline is considered to be particularly dangerous, due to poor access to the beach (and, more importantly, poor egress should one get into trouble), the unstable nature of the cliffs, and the uneven nature of the beach below, which is muddy and strewn with large boulders.

See also...

Follow Sciency Thoughts on Facebook.

Sunday 28 October 2018

Tosanoides aphrodite: A new species of Anthia from the St. Paul’s Rocks in the Mid Atlantic.

Anthias (Anthiinae), or  are small brightly coloured fish belonging to the Grouper Family (Serranidae) in the Perch Order (Perciformes). They are found in large numbers on many coral reefs, and tend to be highly endemic (i.e. species tend to have limited ranges), leading to a large number of different species. The variety, bright colouration and sociable nature of Anthias make them popular in the aquarium trade. All Anthias are born female, and join the harem of a male that controls a section of reef upon reaching maturity. Anthias grow throughout their lives, and when a male dies the largest female in his harem will  change sex, becoming male and taking over the harem.

In a paper published in the journal ZooKeys on 25 September 2018, Hudson Pinheiro, Claudia Rocha, and Luiz Rocha of the California Academy of Sciences describe a new species of Anthia from the St. Paul's Rocks, an uninhabited volcanic archipelago on the Mid Atlantic Ridge belonging to Brazil.

The new species is placed in the genus Tosanoides, and given the specific name aphrodite, in reference to the ancient Greek love goddess. The species is described from three adult males, two adult females and two juvenile females. The juveniles are 46.2 and 52.5 mm in length, the adult females 63.9 and 73.4 mm in length, and the males 74.1, 78.3 and 86.9 mm in length. The females and juveniles are a reddish orange in colour, darker above, with faint yellow and red stripes on the body. The males are more brightly coloured, pink and white, with well defined stripes. The species was found living in crevices on a mesophotic Coral reef (i.e. a Coral reef in an area where some light is present, but not enough to allow much photosynthesis) at depths of between 100 and 130 m.

Tosanoides aphrodite in its natural environment, photographed at a depth of 120 m in St. Paul’s Rocks, Brazil. Luiz Rocha in Pinheiro et al. (2018).

See also...

Follow Sciency Thoughts on Facebook.

Asteroid 2018 US1 passes the Earth.

Asteroid 2018 US1 passed by the Earth at a distance of about 880 530 km (2.29 times the average distance between the Earth and the Moon, or 0.59% of the distance between the Earth and the Sun), slightly before 4.30 pm GMT on Sunday 21 October 2018. There was no danger of the asteroid hitting us, though were it to do so it would not have presented a significant threat. 2018 US1 has an estimated equivalent diameter of 7-23 m (i.e. it is estimated that a spherical object with the same volume would be 7-23 m in diameter), and an object of this size would be expected to explode in an airburst (an explosion caused by superheating from friction with the Earth's atmosphere, which is greater than that caused by simply falling, due to the orbital momentum of the asteroid) in the atmosphere between 37 and 20 km above the ground, with only fragmentary material reaching the Earth's surface.

The calculated orbit of 2018 US1. Minor Planet Center.

2018 US1 was discovered on 21 October 2018 (the day of its closest approach to the Earth) by the University of Arizona's Catalina Sky Survey, which is located in the Catalina Mountains north of Tucson. The designation 2018 US1 implies that it was the 53rd asteroid (asteroid S1) discovered in the second half of October 2018 (period 2018 U).
2018 US1 has a 778 day orbital period and an eccentric orbit tilted at an angle of 8.01° to the plane of the Solar System, which takes it from 1.00 AU from the Sun (i.e. the average distance at which the Earth orbits the Sun) to 2.31 AU from the Sun (i.e. 231% of the average distance at which the Earth orbits the Sun, and further from the Sun than the planet Mars). It is therefore classed as an Apollo Group Asteroid (an asteroid that is on average further from the Sun than the Earth, but which does get closer). This means that close encounters between the asteroid and Earth are extremely common, with the last having occurred in September 2003 and the next predicted in August 2022.

See also...

Follow Sciency Thoughts on Facebook.

Piranhamesodon pinnatomus: A Piranha-like Pycnodont Fish from the Late Jurassic Solnhofen Limestone.

Pycnodont Fish were a highly successful group of Ray-finned Fish, Actinopterygii, that tended to be highly laterally compressed, with deep bodies, and lacked the evertable jaws of modern Teleosts, but often had specialised dentition, with many species apparently being durophagous (adapted to crush the shells of organisms such as Molluscs). They first appeared in the Late Triassic of Europe, and became a dominant group of Fish in many ecosystems in the Late Jurassic and Cretaceous, finally going extinct around the end of the Eocene. However Pycnodont Fish from the Early and Middle Jurassic are very rare, with only about twelve species known, suggesting that this group was very badly affected by the End Triassic Extinction.

In a paper published in the journal Current Biology on 18 October 2018, Martina Kölbl-Ebert and Martin Ebert of the Jura-Museum Eichstätt of the Staatliche Naturwissenschaftliche Sammlungen Bayerns, David Bellwood of the College of Science and Engineering and ARC Centre of Excellence for Coral Reef Studies at James Cook University, and Christian Schulbert of the GeoZentrum Nordbayern at the Friedrich-Alexander Universität Erlangen-Nürnberg, describe a remarkable new Pycnodont Fish from the Solnhofen Limestone of Bavaria.

The new species is described from a single, almost complete specimen on a split limestone block. It is 7.1 cm in length, and has the usual Pycnodont shape, with a deep but strongly compressed body, but differs from all over known Pycnodonts in its dentition, having triangular, dagger-shaped teeth, reminiscent of a modern Piranha. The new species is named Piranhamesodon pinnatomus, where 'Piranhamesodon' is a combination of 'Piranha' and 'Mesodon' a previously described species of Pycnodont, and 'pinnatomus' means 'fin-cutter'.

The Pycnodontiform Piranhamesodon pinnatomus, 7.1 cm standard length, from the Late Jurassic of Ettling, Solnhofen Archipelago, Germany, the earliest fin-cutting Piranha-like Ray Finned Fish. Martin Ebert in Kölbl-Ebert et al. (2018).

A number of other species of Fish described from the Solnhoffen Limestone have been observed to have had what appear to be bite-marks on their fins, consistent with having been attacked by some unknown predator, though no likely candidate has been available to date; numerous Fish species have previously been described from these deposits, but none has had appropriate dentition to do this sort of damage. Kölbl-Ebert et al. suggest that Piranhamesodon pinnatomus would be a very good candidate for causing such damage, as it has both Piranha-like dentition, and a morphology which, like that of other Pcynodonts, is suggestive of a very hard biting-capacity. Coming from the Late Jurassic, Piranhamesodon pinnatomus is not only an example of convergent evolution with modern Piranhas, but is the oldest known example of a Ray-finned Fish with specialist cutting teeth.

See also...

Follow Sciency Thoughts on Facebook.

Woman attacked by Crocodile in Odisha State, India.

A woman is being treated for severe injuries following an attack by a Crocodile in Kendrapara District, Odisha, on Saturday 27 October 2018. The woman, identified as Chhaila Das from the village of Balabhadraprasad was attacked by a five meter long Saltwater Crocodile, Crocodylus porosus, while bathing in a stream near her home. She was initially treated at a local medical centre, before being transferred to the SCB Medical College and Hospital in Cuttack, where her condition is described as critical.

A Saltwater Crocodile, Crocodylus porosus, in the Bhitarkanika National Park in Kendrapara District, Odisha. Anubhav Sarangi/Wikimedia Commons.

Crocodile attacks on Humans are relatively rare, but they are opportunistic ambush predators and will potentially attack anything going close to the water. Saltwater Crocodiles have a particularly poor reputation for such behaviour, being the largest species of Crocodile and notoriously aggressive. These Crocodiles are one of the few Crocodile species not considered vulnerable to extinction, being found from India to Australia  and inhabiting many areas that Humans shun, such as Mangrove forests and islands without fresh water.

The attack occurred close to the Bhitarkanika National Park, which is home to a population of about 1700 Crocodiles, leading to the potential for conflict with humans. The Indian Forest Service has placed barriers along the Bramahani, Kharosotra, Hansua and Baitarani rivers in and around the park, and issued warnings to villagers not to enter the water, though it is unclear to what extent this is a realistic expectation. Local villagers claim an average of about six people are attacked by Crocodiles in the area each year, though the majority of these attacks go unreported, as people simply disappear.

See also...

Follow Sciency Thoughts on Facebook.