Friday 31 May 2019

Mount Etna enters new eruptive phase.

The Etna Observatory of the Istituto Nazionale di Geofisica e Vulcanologia has reported a new eruption on Mount Etna, Sicily. The volcano began to erupt overnight between Wednesday 29 and Friday 30 May, producing a dense column of ash that persisted till the afternoon of Thursday 30 May. Following which three new fissures opened up around the New Southeast Crater (a feature which itself appeared in December 2018), two to the southeast and one to the northeast, which produced lava fountains and flows which ran down into the Valle del Bove, the longest reaching about 3 km from the northeast fissure.

The eruptive scene at dawn on 31 May 2019, as recorded by the high-resolution surveillance camera installed at Monte Cagliato, on the eastern slope of Etna, at the lower end of the Valle del Bove. Istituto Nazionale di Geofisica e Vulcanologia.

Etna first erupted about half a million years ago, beneath the sea off the east coast of Sicily, and has been going strong ever since. It now stands 3330 m above sea level, and covers 1200 km³. It is responsible for fertile soils across eastern Sicily. Records of eruptions on Etna go back to 1500 BC. It is Europe's second largest volcano, after Teide in the Canary Islands, and is one of the most active volcanoes in the world.

 Lava fountains and flows on Mount Etna this week. BBC.

Despite all this Etna has only ever caused 77 recorded deaths (the most recent being two tourists caught in a summit explosion in 1987) and relatively little destruction. In 1928 it destroyed the village of Mascali on its northeastern flank, though there were no reported casualties, the village being slowly overrun by a lava flow. In 1669 a much larger lava flow destroyed at least 10 villages, reaching the walls of the city of Catania, 40 km to the south, but again without loss of life. In 122 BC a heavy ash fall covered much of the region, causing several buildings to collapse in Catania. The destruction was deemed so severe by the Roman authorities that they granted the city a 10 year tax holiday. In about 6000 BC a landslide on the eastern flank of the volcano is thought to have caused a tsunami that caused destruction around much of the eastern Mediterranean. 

 The location of Mount Etna. Google Maps.
Etna is located on the border of the African and European Plates, specifically where Africa is being subducted beneath the European Plate. As it is drawn into the Earth's interior material from the African Plate melts, and the lighter portions rise up through the overlying European Plate, causing a number of volcanoes including Etna and Vesuvius.

 Map showing the tectonic plates underlying Italy and southern Europe, and the location of the l'Aquila Earthquake. Napoli Unplugged.

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Wednesday 29 May 2019

Extremophilic Micro-organismss from the Dallol Geothermal Springs of the Danakil Depression in northern Ethiopia.

Extremophilic organisms live, and often thrive, in environments that would be immediately lethal to most other life, such as boiling hot springs, hyperardid deserts, in strong acids, or in the presence of high levels of heavy metals or salts. The study of such organisms helps scientists to understand the limits at which life can exist, and can potentially give us insights into the potential for life on other planets. The Danakil Depression of northern Ethiopia is extremely volcanically active, with dozens of volcanoes fed by an emerging divergent margin along the East African Rift; Erta Ale is on the Ethiopian Rift, the boundary between the Nubian Plate and the Danakil Microplate. This creates a series of volcanic systems within what is one of the hottest and driest deserts on Earth. The Dallol Geothermal Springs of the Danakil Depression are thought to have formed in 1926 following a phraetic eruption (explosion caused by water coming into contact with hot magma). The water that reaches the surface here is typically at boiling point (~100°C), highly acidic (pH ~0), and saturated with salts and heavy metals and salts, creating a series of pools of varying colours, which reflect their metal contents. The system has been proposed as a possible Earthly analogue of the Nili Patera Caldera on Mars, which is interpreted as an ancient hydrothermal volcanic system.

In a paper published in the journal Scientific Reports on 27 May 2019, Felipe Gómez of the Centro de Astrobiología, Barbara Cavalazzi of the Dipartimento di Scienze Biologiche, Geologiche e Ambientali at the Università di Bologna, and the Department of Geology at the University of Johannesburg, Nuria Rodríguez, also of the Centro de Astrobiología, Ricardo Amils, again of the Centro de Astrobiología, and of the Centro de Biología Molecular “Severo Ochoa” Cantoblanco, Gian Gabriele Ori of the International Research School of Planetary Sciences at the Universitá d’Annunzio, and the Ibn Battuta Centre at the Université Cadi Ayyad, Karen Olsson-Francis of the School of Environment, Earth and Ecosystems Sciences at the Open University, Cristina Escudero and Jose Martínez, also of the Centro de Biología Molecular “Severo Ochoa” Cantoblanco, and Hagos Miruts of the Department of Earth Sciences at Mekelle University, describe the presence of Extremophilic Micro-organismss from the Dallol Geothermal Springs.

The site contained numerous 'chimneys', formed where superheated water reaches the surface and precipitates out its mineral content. Gómez et al. extracted samples from one of these chimneys, as well as the pool surrounding it. The water within the chimney was found to be pH 0.25 and 86 °C, while that in the pool was pH 2.42 and 47 °C.

Panoramic view of the sampling sites (D9: central small chimney and D10: water from the blue pool at the bottom of the chimney). Gómez et al. (2019).

DNA was successfully extracted from the salt precipitates at the chimney; this was found to have come from an unknown Nanohaloarchaean (member of a group of very small, extemophilic Archaeans), which appears to be related to an as-yet-unnamed strain from a salt pond in Alicante, referred to as Candidatus Holaredivivus sp. G17. Scanning electron microscopy of salt crystals from the chimney revealed the presence of small micro-organisms entombed within precipitated silica minerals, which may suggest that the micro-organisms play a role in the mineralisation process.Hot Sp

(A) General view of the sampling site, (B) the small chimneys (temperature of water 90 °C. (C) D9 sample from a small chimney in (A). (D–L) SEM and (M–O) Scanning TEM images of sample D9 showing the morphologies of ultra-small microorganisms entombed in the mineral layers. Gómez et al. (2019).

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Asteroid 2019 KL passes the Earth.

Asteroid 2019 KL passed by the Earth at a distance of about 787 900 km (2.10 times the average distance between the Earth and the Moon, or 0.53% of the distance between the Earth and the Sun), slightly before 3.45 pm GMT on Saturday 25 May 2019. There was no danger of the asteroid hitting us, though were it to do so it would not have presented a significant threat. 2019 KL has an estimated equivalent diameter of 18 m (i.e. it is estimated that a spherical object with the same volume would be 18 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 about 25 km above the ground, with only fragmentary material reaching the Earth's surface.

  The calculated orbit of 2019 KL. Minor Planet Center.

2019 KL was discovered on 24 May 2019 (the day before its closest approach to the Earth)  by the Gruppo Astrofili della Montagna's Osservatorio Astronomico della Montagna Pistoiese. The designation 2019 KL implies that it was the eleventh asteroid (asteroid L - in numbering asteroids the letters A-Y, excluding I, are assigned numbers from 1 to 24, with a number added to the end each time the alphabet is ended, so that A = 1, A1 = 25, A2 = 49, etc., which means that L = 11) discovered in the second half of May 2019 (period 2019 K).
2019 KL has an 800 day orbital period and an eccentric orbit tilted at an angle of 19.0° to the plane of the Solar System, which takes it from 0.92 AU from the Sun (i.e. 92% of he average distance at which the Earth orbits the Sun) to 2.45 AU from the Sun (i.e. 245% of the average distance at which the Earth orbits the Sun, and outside the orbit of 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). 

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Tuesday 28 May 2019

Gujarat woman killed by Leopard.

A 52-year-old woman has died after being attacked by a Leopard on Monday 27 May 2019. Shardaben Vavaiya was apparently attacked in her own home while sleeping alone in the village of Kankchiyala in Junagadh District, with the animal seizing her by the throat and attempting to drag be from the building, before abandoning her body, Officials from the Indian Forest Service have been called in and are attempting to capture the Leopard. This is the third fatal Leopard attack in Junagadh District in the last two months, with the other victims being another woman and a girl.

A Leopard in the Gir National Park in Gujarat. Dhaval Vargiya/Wikimedia Commons.

Leopards are considered to be Vulnerable under the terms of the International Union for the Conservation of Nature's Red List of Threatened Species, with the Indian subspecies, Panthera pardus fusca, considered to be particularly vulnerable due to India's rapidly rising Human population, which has resulted in agriculture and other Human activities expanding into many former wilderness areas. For this reason the Indian Forest Service usually try to relocate Leopards that come into conflict with Humans to more remote areas, preferably within national parks, though the extent to which local people co-operate is variable.

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Monday 27 May 2019

Limonium dagmarae: A new species of Sea Lavender from the Namaqualand Coast of South Africa.

Members of the genus Limonium are known as Sea Lavenders, or sometimes Marsh Rosemarys, though they are actually members of the Leadwort Family, Plumbaginaceae. They form woody herbaceous perennials or small shrubs, favouring saline or alkaline soils that most plants avoid, and are widely cultivated as ornamental garden plants. Sea Lavenders are found in Africa, Eurasia, North America and Australia, though they reach their maximum diversity around the Mediterranean Basin. A distinct cluster of species found in Southern Africa was formerly classified as a separate genus, Afrolimon, though this has not been supported by genetic evidence, and these species are now considered to be part of the genus Limonium.

In a paper published in the journal Phytotaxa on 10 May 2019, Ladislav Mucina of the Harry Butler Institute at Murdoch University, and the Department of Geography and Environmental Studies at Stellenbosch University, and Timothy Hammer of the School of Biological Sciences at the University of Western Australia, describe a new species of Sea Lavender from the Namaqualand Coast of South Africa.

The new species is named Limonium dagmarae, in honour of Dagmar Mucina, the wife of Ladislav Mucina, for her passion for the flora of Namaqualand. This species is a small shrub, forming bushes about 60 cm high, with copper-coloured woody stems and densely packed, waxy, oval leaves in an alternating arrangement. Flowers are numerous, tubular, about 5 mm in length, and produced between August and November.

Limonium dagmarae in situ, from the southernmost population of the species; overall habit (semiglobose-shaped low shrub). Ladislav Mucina in Murcina & Hammer (2019).

Limonium dagmarae  is found along a strip of the Namaqualand Coast roughly 205 km long and 5-10 km wide, typically occuring in groups of several tens of individuals. Most of the land where it occurs is privately owned, and used for pasture, with much of it potentially vulnerable to development. For these reasons Murcina and Hammer recommend that the species be classified as Endangered under the terms of the International Union for the Conservation of Nature's Red List of Threatened Species.

Limonium dagmarae in situ, from the southernmost population of the species. (B) View of a branch that finished flowering not long ago (the papery calyces are still light pink and brownish ribs prominent; also showing the sparse leafing of the branch. (C) Fully developed flower, flanked by several calyces which perigone already withered and several buds prepared to flower. (D) Habitat of Limonium dagmarae; loamy-sandy strandveld scrub, with associated succulent shrubs. Ladislav Mucina in Murcina & Hammer (2019).

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Leptospirosis kills eight in FIji.

Eight people have now been confirmed dead in an outbreak of Leptospirosis  in Fiji that began in January this year (2019). Five people died in the January-April period, with a further three deaths reported over the Easter Period (19-22 April). At least 400 more people have been infected with the disease, which is principally contracted from animal urine, and can reach epidemic proportions when flooding occurs, as has happened in Fiji this year.

Flooding in Labasa, Fiji, in January 2019. The Fiji Times.

Leptospirosis is caused by a number of Bacteria in the genus Leptospira, Spirochaete Bacteria related to Borrelia burgdorferi (Lyme Disease) and Treponema pallidum (Syphilis). It typically manifests as a bout of severe fever, followed by several days of apparent recovery, then a second bout of fever which may be accompanied by meningitis and/or acute liver failure. The disease can be encountered worldwide, but in developed countries is rare except in those who work with livestock. However in areas of developing countries with poor sanitation outbreaks of Leptospirosisis can reach epidemic proportions during periods of flooding,

 SEM image of Leptospira interrogans, one of the causative agents of Leptospirosis. Janice Carr/Centers for Disease Control and Prevention/National Center for Infectious Diseases/Wikimedia Commons.

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Magnitude 4.4 Earthquake in Badakhshan Province, Afghanistan.

The United States Geological Survey recorded a Magnitude 4.4 Earthquake at a depth of 240.4 km, roughly 34 km to the southwest of the village of Jarm in Badakhshan Province, Afghanistan, slightly after 1.35 pm local time (slightly after 9.05 am GMT) on Sunday 26 May 2019. Quakes at this depth are seldom dangerous, but are often felt over a wide area, and this one was reportedly felt in Aybak in Samangan Province, roughly 200 km to the northeast of the epicentre.

The approximate location of the 26 May 2019 Badakhshan Earthquake. USGS.

The boundary between the Indian and Eurasian tectonic plates 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.

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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