Eight dead and five missing following landslide in Kozhikode District, Kerala.

Eight people, including four children, have been confirmed dead and another five are still missing, following a landslide which hit the village of Kattipara in Kozhikode District, Kerala, on Thursday 14 Jube 2018. The deceased have been named as Dilna, 13, Muhammad Shahabad, 7, Abdur Rahman, 60, Jannat, 25, Muhammad Jaseem, 5, Hassan, 67 and Jaffar, 45 and Rippa Mariam, 1½. The landslide is thought to have been caused by heavy rains associated with the Southwest Monsoon, which arrived in Kerala about six weeks ago, and brings the number of deaths attributed to flooding and landslides associated with the monsoon in the state this year to 43.

Rescue workers looking for survivors following a landslide that hit the village of Kattipara in Kozhikode District, Kerala, on 14 June 2018. Press Trust of India.

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.

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

Kerala has a complex seasonal cycle, driven by the presence of the Western Ghats mountain range, which largely block the dry northerly winds which dominate the climate of much of India, and its proximity to the equator, which leads to a double monsoon system. Such a double Monsoon Season is common close to the equator, where the Sun is highest overhead around the equinoxes and lowest on the horizons around the solstices, making the solstices the coolest part of the year and the equinoxes the hottest. In Kerala this results in a Southwest Monsoon, which lasts from May to September, and is driven by winds from the southern Arabian Sea dumping water onto the Western Ghats, followed by a Northwest Monsoon, which lasts from October to December, where winds from the Bay of Bengal do the same. Of the two monsoons, the southwest is the wetter, due to the proximity of the sea, with June typically being the wettest month, with an average of 341 mm of rain falling in the month.

Flooding below the village of Kattipara in the Thamarassery Churam mountain passage in Kerala State, India. ANI.

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Arkansas kayaker killed when sinkhole opens up beneath river.

An Arkansas kayaker died on Saturday 9 June 2018 when a sinkhole opened up on a river bed, creating a whirlpool that sucked him in. Donald Wright, 64, from Searcy, was transversing a section of the Spring River known as Dead Man's Curve in Fulton County, when the sinkhole opened up, creating a strongly swirling vortex as water was drawn into an underground cavern. A second kayaker was injured in the incident.

Whirlpool on the Spring River in Arkansas that formed when a sinkhole opened up beneath the river on 9 June 2018. AP.

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.

On this occassion the sinkhole is thought to have formed when the action of the river eroded limestone on the riverbed until it exposed an underground cave system, itself the ptoduct of thousands of years of erosion by water percolating through the rock, suddenly exposing a void beneath the river which caused the whirlpool to form. In time the cave is expected to fill with water, and the whirlpool will disappear.

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Poachers kill tame Elephant in Aceh Province, Sumatra.

A tame Elephant has been killed by poachers in the Serbajadi District of Aceh Province, Sumatra, Indonesia. Bunta, 27, was one of a herd of four Sumatran Elephants, Elephas maximus sumatranus, kept by the Serbajadi Conservation Response Unit in the village of Bunin, and used to help prevent Human-Elephant conflict by warding off wild Elephants approaching agricultural land. He was found dead on Sunday 10 June 2018, having apparently died after consuming Bananas and Mangoes laced with poison, and had subsequently had one tusk removed.

The body of Bunta, a 26-year-old Sumatran Elephant from a herd owned by the Serbajadi Conservation Response Unit Conservation Response Unit, killed by poachers this weekend. Al Mahdi/Antara.

The Sumatran Elephants, Elephas maximus sumatranus, is a subspecies of Asian Elephant, Elephas maximus, which was once found across the island of Sumatra, but which is now restricted to 25 fragmented populations, most of which are located outside of conservation areas, a drop from 43 populations in 1985, with the total wild population estimated at 2400-2800 individuals. For this reason the Sumatran Elephant is considered to be Critically Endangered under the terms of the International Union for the Conservation of Nature’s Red List of Threatened Species.

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Martian dust strom forces Opportunity Rover to enter Hibernation.

NASA's Opportunity Rover has been forced to enter hibernation mode after a large dust storm developed in Mars's equatorial region. The storm, which was first observed on 1 June 2018, currently covers an area of about 18 million square kilometres, including Perseverance Valley, where the rover is currently located. While the thin atmosphere of Mars cannot support sandstorms like those on Earth, which can cause damage via abrasion, they can lift significant quantities of dust particles, which significantly reduce the amount of light reaching the rover, which is powered by solar panels, cutting the power available to the rover both to operate and to keep itself warm. 

Photo-montage map of Mars showing the growing dust storm on June 6, 2018. The blue dot shows the approximate location of the Opportunity Rover. NASA/JPL/Caltech/Malin Space Science Systems.

Warmth is an important consideration for any device operating on Mars, where temperatures are significantly cooler than on Earth (the current average daily temperature in the Perseverance Valley is about -29°C). This means that a sustained storm could potentially leave the rover with batteries to drained for it to warm itself to an operational temperature, a fate that befell the Spirit Rover in 2008.

The Opportunity Rover. NASA.

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Magnitude 3.9 Earthquake to the soitheast of Hull, East Yorkshire.

The British Geological Survey recorded a Magnitude 3.9 Earthquake at a depth of 18 km, about 14 km to the southeast of the city of Hull in East Yorkshire, England, slightly before 11.15 pm British Summertime (slightly before 10.15 pm GMT) on Saturday 9 June 2018. There are no reports of any damage or casualties associated with this event, but it was felt as far away as the southern Scottish Highlands and the south coast of England.

 

 The approximate location of the 9 June 2018 Hull 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. 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 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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Asteroid 2004 LB passes the Earth.

Asteroid 2004 LB passed by the Earth at a distance of about 18 954 000 km (48.3 times the average distance between the Earth and the Moon, or 12.7% of the distance between the Earth and the Sun), slightly after 2.00 pm GMT on Wednesday 6 June 2018. There was no danger of the asteroid hitting us, though were it to do so it would have presented a significant threat. 2004 LB has an estimated equivalent diameter of 90-280 m (i.e. it is estimated that a spherical object with the same volume would be 90-280 m in diameter), and an object at the upper end of this range would be predicted to be capable of passing through the Earth's atmosphere relatively intact, impacting the ground directly with an explosion that would be about 60 000 times as powerful as the Hiroshima bomb. Such an impact would result in an impact crater about 4.5 km in diameter and devastation on a global scale, as well as climatic effects that would last years or even decades.

The calculated orbit of 2004 LB. Minor Planet Center.

2004 LB was discovered on 7 June 2004 by the Lowell Observatory Near-Earth-Object Search, at Anderson Mesa Station, near Flagstaff, Arizona. The designation 2004 LB implies that it was the second asteroid (asteroid B) discovered in the first half of June 2004 (period 2004 L),

2004 LB has an 394 day orbital period and an eccentric orbit tilted at an angle of 37.3° 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 1.11 AU from the Sun (i.e. 111% of the average distance at which the Earth orbits the Sun). 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 November 2017 and the next predicted in December 2018. As an asteroid probably larger than 150 m in diameter that occasionally comes within 0.05 AU of the Earth, 2004 LB is also classified as a Potentially Hazardous Asteroid.

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