Hurricane Dorian confirmed to have killed seven in the Bahamas and one in North Carolina.

Eight people have now been confirmed dead as Hurricane Dorian passed over the Bahamas and up the east coast of the United States. The hurricane swept past several Caribbean island nations between 25 and 30 August 2019, prompting evacuations and curfews, but causing little actual damage. However, over this period it was steadily gaining in strength, so that when it finally made landfall on Elbow Cay in the Bahamas it was a Category Five storm, with sustained winds in excess of 250 km per hour and gusts considerably stronger, and the strongest storm ever recorded to have made landfall from the Atlantic. The storm caused widespread devastation across the Abaco Islands and Grand Bahama, destroying thousands of homes causing widespread flooding and killing at least seven people - though this number is likely to be a severe underestimate due to the damage the storm has caused to the nation's infrastructure. Following this the storm has swept northward up the east coast of the United States, past Florida, Georgia, and South and North Carolina. The storm has brought flooding and high winds to these areas, with storm surges in excess of two metres and one confirmed death in North Carolina, but has been losing strength as it moves north and is now only a Category Two storm.

Flooding and damaged buildings in the Abaco Islands in the wake of Hurricane Dorian. Latrae Rahming.

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.

 The path and strength of Hurricane Dorian. Thick line indicates the past path of the storm (till 3.00 pm GMT on Tuesday 4 September 2019), while the thin line indicates the predicted future path of the storm, and the dotted circles the margin of error at nine, twenty one, thirty three, forty five, sixty nine, ninety three and one hundred and seventeen 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. 

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Magnitude 1.1 Earthquake in Surrey, England.

The British Geological Survey recorded a Magnitude 1.1 Earthquake at a depth of 2 km, about 1 km to the south of Norwood Hill in Surrey, England, slightly before 6.15 am GMT (slightly before 5.15 am GMT) on Monday 2 September 2019. There are no reports of any damage or casualties associated with this Earthquake, and nor would they be expected with such a small event, people have reported feeling it locally. 

The approximate location of the 2 September 2019 Surrey Earthquake. Google Maps.

This is the latest in a series of shallow Earthquakes in the area, which began with a Magnitude 2.6 event on 1 April 2018, the first recorded Earthquake in Surrey in over 268 years, and included a Magnitude 2.4 event on 14 February,  Magnitude 2.0 event on 19 February, and magnitude 3.1 event on 27 February this year. Local residentshave raised concerns that these events may be linked to oil and gas exploration in the region, and have formed a protest group, Frack Free Surrey, which has called for a moratorium on such activities, a demand which has won the support of several senior British geologists, though the British Geological Survey has not been able to establish a link between the Earthquakes and the drilling, and the companies involved UK Oil & Gas PLC, and Angus Energy, deny such a link is even possible.

Letter written to The Times newspaper in London in August 2019, by four senior British geologists, Stuart Gilfillan, Stuart Haszeldine, Bill McGuire, and Richard Selley, calling for a moratorium on explorationary oil drilling in Surrey. Drill or Drop?

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. However, while quakes in southern England are less frequent, they are often larger than events in the north, as tectonic pressures tend to build up for longer periods of time between events, so that when they occur more pressure is released.

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.

 (Top) Simplified diagram showing principle of glacial rebound. Wikipedia. (Bottom) Map showing the rate of glacial rebound in various parts of the UK. Note that some parts of England and Wales show negative values, these areas are being pushed down slightly by uplift in Scotland, as the entire landmass is quite rigid and acts a bit like a see-saw. Climate North East.

Witness accounts can help scientists to understand Earthquakes and the geological processes that cause them. If you felt this quake (or if you were in the area and did not, which is also useful information) then you can report it to the British Geological Survey here.

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Berardius minimus: A new species of Beaked Whale from the North Pacific.

Beaked Whales, Ziphiidae, are the second largest group of Toothed Whales in terms of number of species, with 22 species in six genera. Despite this speciousness the group is not well studied, due to their preference for deep water environments and long dive times, which makes them rather hard to study. The genus Berardius currently contains two species, Baird’s Beaked Whale, Berardius bairdii, found in the North Pacific, and Arnoux’s Beaked Whale Berardius arnuxii, found in the Southern Ocean. However, Whalers from Hokkaido, the northernmost of Japan's four main islands, have long recognised two forms of Beaked Whale in the North Pacific, a larger grey form that corresponds to the official description of Baird’s Beaked Whale, and a smaller black form, which might potentially represent a different species.

In a paper published in the journal Scientific Reports on 30 August 2019, Tadasu Yamada of the Department of Zoology at the National Museum of Nature and Science, Shino Kitamura of the Sanriku Fisheries Research Centre, and the Faculty of Fisheries Sciences at Hokkaido University, Syuiti Abe, also of the Faculty of Fisheries Sciences at Hokkaido University, Yuko Tajima, also of the Department of Zoology at the National Museum of Nature and Science, Ayaka Matsuda, again of the Faculty of Fisheries Sciences at Hokkaido University, James Mead of the Division of Mammals at the Smithsonian Institution, and Takashi Matsuishi, once again of the Department of Zoology at the National Museum of Nature and Science, and of the Global Institution for Collaborative Research and Education at Hokkaido University, formally describe the smaller North Pacific Beaked Whalea as a new species of Berardius.

The new species is named Berardius minimus in reference to its smaller size, and is described on  the basis of six specimens found dead either washed up on beaches or floating close to shore around the island of Hokkaido. The species is notably smaller than both other species of Berardius, with the largest specimen observed being only 6.9 m in length, as well as having a shorter, straighter and narrower beak, being darker in colour, almost black, with prominent white spots, and more prone to bites from Cookie-cutter Sharks. The species was found to be genetically distinct from Berardius bairdii, and to have somewhat different skeletal proportions.

Illustrations of (A) Berardius minimus, and (B) Berardius bairdii. The black bars show 1 m. In general appearance, Berardius minimus resembles a small Berardius bairdii with a proportionately shorter beak and more spindle-shaped body, Yoshimi Watanabe in Yamada et al. (2019).

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Comet C/2018 W2 (Africano) approaches perihelion.

Comet  C/2018 W2 (Africano) will reach its perihelion (the closest point on its orbit to the Sun) on Thursday 5 September 2019, when it will be approximately 1.46 AU from the Sun (i.e. 146% of the distance between the Earth and the Sun, between the orbits of Mars and Jupiter). The comet will be 0.95 AU from the Earth at the time of the perihelion, in the constellation of Perseus seen from the Earth, and it will be visible with a good pair of binoculars, though it is currently moving towards us and on Friday 27 September will make its closest approach to the Earth, when it will be only 0.49 AU away, in the constellation of Pegasus.

Short video of C/2018 W2 (Africano) made on 29 June 2019 by Michael Jager of Stixendorf in Austria. The video is made up of three long exposure photographs, with the comet being the moving object at the centre of the image and the line across the bottom left part of the image being a satellite. Seiichi Yoshida's Comet Page.

Comet C/2018 W2 (Africano) was discovered on 27 November 2018 by Brian Africano of the University of Arizona's Mt. Lemmon Survey at the Steward Observatory on Mount Lemmon in the Catalina Mountains north of Tucson. The designation The name C/2018 W2 (Africano) implies that it is a non-periodic comet (C/) (all comets are, strictly speaking, periodic since they all orbit the Sun, but those with periods longer than 200 years are considered to be non-periodic), that it was the third comet (comet 2) discovered in the second half of November 2018 (period 2018 W) and that it was discovered by Brian Africano.

The orbit and current position of Comet C/2017 T3 (ATLAS). The Sky Live 3D Solar System Simulator.

C/2018 W2 (Africano) has an unknown orbital period and a highly eccentric orbit tilted at an angle of 116° to the plain of the Solar System, that brings it to 1.46 AU from the Sun at perihelion (146% of the distance between the Earth and the Sun, and slightly inside the orbit of Mars).

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Villager attacked by Elephant after collision with car in Thailand.

A villager has been badly injured after being attacked by an Elephant believed to have been in a collision with a car in the Thong Pha Phum District of Kanchanaburi Province in central Thailand on Saturday 31 August 2019. The initial incident happened happened on Highway 323 at about 1.10 am local time, when the animal was hit by a Toyota Fortuner, driven by a Myanmar national identified as Yi Teng, resulting in the vehicle being overturned and the driver injured. Following the incident officials from the Thong Pha Phum National Park and local villagers formed search parties to look for the Elephant, due to concerns that it might be injured. At about 2.00 pm local time a team of three searchers encountered a male Elephant, estimated to have been about 8-10 years old and weighing about 4000 kg, about 500 m from the scene of the original accident. The Elephant attacked the group, resulting in one of the men Tewan Munnut, 26, being trampled and suffering a broken rib and punctured lung. He is being treated at the Phahon Phonphayuhasena Hospital in Kanchanaburi.

 The scene of an accident in which a car was overturned in an encounter with an Elephant in Kanchanaburi Province, Thailand, on 31 August 2019. Kanchanaburi Rescue Foundation.

The wild Elephant population of Thailand has fallen from about 100 000 in 1850 to about 2700, largely due to deforestation and Human expansion into their range. Many animals will simply flee such incursions, or, if unable to, are likely to end up in the cooking pots of hungry villagers. Elephants, however, are a somewhat different proposition. They are large animals, not used to being challenged by other animals in their home ranges, and typically live in matriarchal herds of up to a hundred, with herds holding large territories, criss-crossed by Elephant trails. Elephants encountering Human objects they dislike are unlikely to attempt to go round it, and are quite likely to maximise the damage they cause to show their displeasure.

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Landslide kills three in Jajarkot District, Nepal.

Three people have died following a landslide in the Jajarkot District of Nepal on Sunday 1 September 2019. The incident happened happened at about 1.45 am, hitting the house in which Parbati Wali, 32, and her daughters Motikala, 9, and Dhansara, 3, were sleeping. All three people in the house were killed, with Parbati's husband, Dal Bahadur Wali, surviving with leg injuries as he was sleeping outside.

The scene of a landslide in Jajarkot District, Nepal, on 1 September 2019, that killed three people. Dinesh Kumar Shrestha/Himalayan Times.

Dinesh Kumar Shrestha

Dinesh Kumar Shrestha

Dinesh Kumar Shrestha

The incident has been blamed on torrential rainfall that has fallen across the area in the last few days. Landslides are common during the monsoon season in Nepal, which lasts from May to September, with  the highest rainfall occurring in July. 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.

Monsoons are tropical sea breezes triggered by heating of the land during the warmer part of the year (summer). Both the land and sea are warmed by the Sun, but the land has a lower ability to absorb heat, radiating it back so that the air above landmasses becomes significantly warmer than that over the sea, causing the air above the land to rise and drawing in water from over the sea; since this has also been warmed it carries a high evaporated water content, and brings with it heavy rainfall. In the tropical dry season the situation is reversed, as the air over the land cools more rapidly with the seasons, leading to warmer air over the sea, and thus breezes moving from the shore to the sea (where air is rising more rapidly) and a drying of the climate. This situation is particularly intense in South Asia, due to the presence of the Himalayas. High mountain ranges tend to force winds hitting them upwards, which amplifies the South Asian Summer Monsoon, with higher winds leading to more upward air movement, thus drawing in further air from the sea. 

Diagrammatic representation of wind and rainfall patterns in a tropical monsoon climate. Geosciences/University of Arizona.

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Magnitude 5.5 Earthquake in the Sagaing Region of Myanmar.

The United States Geological Survey recorded a Magnitude 5.5 Earthquake at a depth of 10.0 km in Sagaing Region, Myanmar, about 26 km to the northwest of the city of Shwebo, slightly before 9.40 pm local time (slightly before 3.10 am GMT) on Saturday 31 August 2019. There are no reports of any injuries following this event, though some damage to buildings has occurred. People have reported felling the quake across northern Myanmar, as well as in parts of northeastern India, and Yunnan Province, China.

 

Damage to a pagoda in YayU following an Earthquake in the Sagaing Region of Myanmar on 31 August 2019. Yarza Dhamma Htantapin/Eleven Media.

 

Myanmar is an area fairly prone to Earthquakes; much of the country lies on the Burma Plate, a small tectonic plate caught between  the Eurasian Plate to the northeast, the Indian Plate to the west and southwest and the Sunda Plate to the southeast. As these larger plates move together the Burma Plate is being squeezed and fractured, with a major fault line, the Kabaw Fault, having formed across much of the north of the country, along which the Burma Plate is slowly splitting. Most Earthquakes in the region are caused by movement on this fault.

   

The movement of the Burma and surrounding plates. Sheth et al. (2011).

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.

 

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