Wednesday, 20 June 2018

Flooding kills at least eighteen in Abidjan, Côte d'Ivoire.

At least eighteen people died in flooding in Abidjan, Côte d'Ivoire, on Monday 18-Tuesday 19 June 2018, with over a hundred needing to be rescued by emergency services and many more escaping on their own. The flooding was caused by torrential rain overnight, associated with the West African Rainy Season, which has been particularly severe this year due to high temperatures over the Gulf of Guinea, leading to more water evaporating from the sea surface, and therefore more falling on land. 

The aftermath of a flash flood in Abidjan on 19 June 2018. Luc Gnago/Reuters.

The rains began at about 11.00 pm, and persisted till about 6.00 am, causing a sting of flash floods that in places reached 2.5 m deep. Abidjan has become increasingly prone to flash flooding due to rapid urban expansion in the area (the population of Côte d'Ivoire has doubled since 1990), which is built on an area of historic coastal wetlands, preventing rainwater from draining into the soil and raising the dangers of flooding in the city.

June falls in the middle of the rainy season in Abidjan, with the city receiving an average of 568.1 mm of rain during the month. West Africa has a distinct two season climatic cycle, with a cool dry season during the northern winter when prevalent winds blow from the Sahara to the northeast, and a warm rainy season during the northern summer when prevalent winds blow from the Atlantic Ocean to the southwest. These warm winds from the Atlantic are laden with moisture, which can be lost rapidly when the air encounters cooler conditions, such as when it is pushed up to higher altitudes by the Ivorian plateaux.

 Rainfall and prevalent winds during the West African dry and rainy seasons. Encyclopedia Britanica.

See also...

http://sciencythoughts.blogspot.com/2018/04/poaching-in-kakum-conservation-area-of.htmlhttp://sciencythoughts.blogspot.com/2017/10/unsustainable-chocolate-production.html
http://sciencythoughts.blogspot.com/2017/07/landslide-kills-at-leat-three-at-guinea.htmlhttp://sciencythoughts.blogspot.com/2015/11/evidence-for-sexual-transmission-of.html
http://sciencythoughts.blogspot.com/2015/05/pathogenic-oomycete-chromists-from-new.htmlhttp://sciencythoughts.blogspot.com/2015/01/the-source-of-december-2013-guinean.html
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Asteroid 2018 LD1 passes the Earth.

Asteroid 2018 LD1 passed by the Earth at a distance of about 601 400 km (1.58 times the average  distance between the Earth and the Moon, or 0.02% of the distance between the Earth and the Sun), at about 4.00 pm GMT on Thursday 14 June 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 LD1 has an estimated equivalent diameter of 11-34 m (i.e. it is estimated that a spherical object with the same volume would be 11-34 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 30 and 10 km above the ground, with only fragmentary material reaching the Earth's surface.

The calculated orbit of 2018 LD1. Minor Planet Center.

2018 LD1 was discovered on 5 June 2018 (nine days before its closest approach to the Earth) by the University of Hawaii's PANSTARRS telescope. The designation 2018 LD1 implies that the asteroid was the 29th object (object D1) discovered in the first half of June 2018 (period 2018 L).   

2019 LD1 has a 929 day orbital period and an eccentric orbit tilted at an angle of 0.35° to the plane of the Solar System, which takes it from 0.91 AU from the Sun (i.e. 91% of he average distance at which the Earth orbits the Sun) to 2.82 AU from the Sun (i.e. 282% 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).

See also...

http://sciencythoughts.blogspot.com/2018/06/fireball-meteor-over-belgium.htmlhttp://sciencythoughts.blogspot.com/2018/06/asteroid-2015-dp155-passes-earth.html
http://sciencythoughts.blogspot.com/2018/06/asteroid-2004-lb-passes-earth.htmlhttp://sciencythoughts.blogspot.com/2018/06/meteorites-found-in-yunnan-province.html
http://sciencythoughts.blogspot.com/2018/06/asteroid-2018-la-impacts-earth.htmlhttp://sciencythoughts.blogspot.com/2018/05/asteroid-2019-kw1-passes-earth.html
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Magnitude 5.9 Earthquake in Osaka Prefecture results in three fatalities and over 200 injuries.

The Japan Meteorological Agency recorded a Magnitude 5.9 Earthquake at a depth of about 10 km, beneath Osaka Prefecture on Honshū Island, slightly before 8.00 am Japan Standard Time  on Monday 18 June 2018 (slightly before 11.00 pm on Sunday 17 June GMT). The Earthquake is known to have resulted in three fatalities, a nine year old girl and two men in their eighties, as well as at least 217 injuries, and left about 170 000 households without power, as well as causing severe disruption to public transport networks.

Damaged goods in a supermarket following the 18 June 2018 Osaka Earthquake. Reuters.

Japan has a complex tectonic situation, with parts of the country on four different tectonic plates. Eastern Honshū area lies on the boundary between the Pacific, Eurasian and Philippine Plates, where the Pacific Plate is passing beneath the Eurasian and Philippine Plates as it is subducted into the Earth. This is not a smooth process; the rocks of the two plates constantly stick together, only to break apart again as the pressure builds up, causing Earthquakes in the process.

The movement of the Pacific and Philippine Plates beneath eastern Honshū. Laurent Jolivet/Institut des Sciences de la Terre d'Orléans/Sciences de la Terre et de l'Environnement.

\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...
 
http://sciencythoughts.blogspot.com/2018/05/magnitude-53-earthquake-beneath-chiba.htmlhttp://sciencythoughts.blogspot.co.uk/2018/04/eruption-on-io-yama-volcano-japan.html
http://sciencythoughts.blogspot.co.uk/2018/04/ongoing-eruptions-on-mount-shinmoedake.htmlhttp://sciencythoughts.blogspot.co.uk/2018/03/further-eruptions-on-mount-shinmoedake.html
http://sciencythoughts.blogspot.co.uk/2018/03/eruption-on-mount-shinmoedake.htmlhttp://sciencythoughts.blogspot.co.uk/2017/10/eruption-on-mount-shinmoedake-kyushu.html
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Northern Solstice 2018.

The Northern) Solstice falls on Thursday 21 June in 2018, the day on which the Sun rises highest in the sky and the longest day of the year in the Northern Hemisphere (where it is the Summer Solstice) and the day on which the Sun rises lowest in the sky and the shortest day in the Southern Hemisphere (where it is the Winter Solstice). Up until this date the days have been growing longer in the Northern Hemisphere and shorter in the Southern Hemisphere since the Southern Solstice in December 2017 (which is the Winter Solstice in the Northern Hemisphere and Summer Solstice in the Southern Hemisphere), but after it the situation will be reversed, with days growing steadily shorter in the Northern Hemisphere and longer in the Southern Hemisphere until the next Southern Solstice in December this year..

The solstices are entirely a product of variation in the Earth's rotation on its axis, which is at an angle of 23.5° to the plain of the Earth's orbit about the Sun. This means that in December the Earth's Southern Pole is tilted towards the Sun, while the Northern Pole is tilted away from it. This means that around the Southern Solstice the Southern Hemisphere is receiving radiation from the Sun over a longer part of the than the Northern, and at a steeper angle (so that it to pass through less atmosphere to reach the planet), creating the southern summer and northern winter.
 
The tilt of the Earth at the Northern Solstice. Wikimedia Commons.

The solstices are fairly noticeable astronomical events, and tied to the seasons which govern the life cycles of life on Earth, and they have been celebrated under different names by cultures across the globe, but most notably by those at higher latitudes, who are more profoundly affected by the changes of the seasons.

See also...

http://sciencythoughts.blogspot.com/2018/04/uranus-reaches-solar-conjunction.htmlhttp://sciencythoughts.blogspot.com/2018/03/the-march-equinox.html
http://sciencythoughts.blogspot.co.uk/2018/02/partial-solar-eclipse-to-be-visible.html\http://sciencythoughts.blogspot.co.uk/2018/03/neptune-reaches-solar-conjunction.html
http://sciencythoughts.blogspot.co.uk/2018/01/total-lunar-eclipse-on-31-january-2018.htmlhttp://sciencythoughts.blogspot.co.uk/2017/12/earth-approaches-perihelion.html
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Tuesday, 19 June 2018

Landslide kills three in Zhob District, Pakistan.

Three members of the same family have died and two more have been injured, after a landslide at Silyazzai in the Zhob District of Balochistan Province, Pakistan, on Sunday 17 June 2018,  Those involved are reported to be the family of Rahmatullah Safi, a freelance photographer and politician, who were visiting a local beauty spot as part of the Eid celebrations when the event occurred. The deceased have been identified as Najeebullah, 8, Raza Gul, 10, and Mohibullah, 13, while Rahmatullah Safi himself and an older son were injured.

Vehicle belonging to Rahmatullah Safi, destroyed in the 17 June 2018 Silyazzai landslide. Hafeezullah Sherani/Dawn.

The incident is reported to have occurred following heavy rains in the area associated with the Indian Summer Monsoon. 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. Zhob is an arid area which is not always reached by the monsoon, but this means that when the rains do reach it then it is particularly vulnerable to landslips, due to a lack of vegetation, which can help hold soil layers together and prevent such events.


The approximate location of the 17 June 2018 Silyazzia landslide. Google Maps.

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.

See also...

http://sciencythoughts.blogspot.com/2018/06/explosion-kills-four-miners-in.htmlhttp://sciencythoughts.blogspot.com/2018/04/balochistan-miners-die-of-gas-poisoning.html
http://sciencythoughts.blogspot.com/2017/02/magnitude-63-earthquake-on-coast-of.htmlhttp://sciencythoughts.blogspot.com/2014/07/magnitude-44-earthquake-in-balochistan.html
http://sciencythoughts.blogspot.com/2013/11/magnitude-49-earthquake-in-northeast.htmlhttp://sciencythoughts.blogspot.com/2013/10/magnitude-53-earthquake-in-eastern.html
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Monday, 18 June 2018

Flooding kills 23 in northeastern India.

Twenty three people have died in flooding in northeastern India since the Southwest Monsoon arrived in the area five days ago. Twelve of the deaths occurred in the state of Assam, where five people died on Sunday 17 June alone, with the remaining deaths occurring in Manipur, and severe flooding also reported in Tripura, and Mizoram. Thousands of people across the region have been forced to abandon homes and farms in the region, and it in addition to the Human casualties, large numbers of livestock have died.

Floodwaters in Assam this week. Anuwar Hazarika/Reuters.

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.

Much of Southeast Asia has two distinct Monsoon Seasons, with a Northeast Monsoon driven by winds from  the South China Sea that lasts from November to February and a Southwest Monsoon driven by winds from the southern Indian Ocean from March to October. 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. However northeast India is largely protected from the Northeast Monsoon by the mountains to its north and east, though these can also add to the severity of flooding in the region, with melting snow in the Himalayas swelling the rivers that flow through these states,

The winds that drive the Northeast and Southwest Monsoons in Southeast Asia. Mynewshub.

See also...

http://sciencythoughts.blogspot.com/2018/05/landslip-at-mizoram-quarry-kills-four.htmlhttp://sciencythoughts.blogspot.com/2017/07/flooding-kills-at-least-seventy-three.html
http://sciencythoughts.blogspot.com/2016/07/woman-killed-by-landslide-in-guwahati.htmlhttp://sciencythoughts.blogspot.com/2016/01/magnitude-67-earthquake-in-manipur.html
http://sciencythoughts.blogspot.com/2014/06/at-least-seven-dead-following-heavy.htmlhttp://sciencythoughts.blogspot.com/2014/05/seven-members-of-one-family-killed-by.html
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