Fireball Meteor over Puget Sound..

The American Meteor Society has received reports of a bright fireball meteor being seen over Puget Sound in Washington State, slightly before 7.00 pm local time on Wednesday 6 May 2020 (slightly before 2.00 am on Thursday 7 May GMT). The meteor passed over the Sound from west to east, disappearing somewhere to the northeast of Seattle. A fireball is defined as a meteor (shooting star) brighter than the planet Venus. These are typically caused by pieces of rock burning up in the atmosphere, but may be the result of man-made space-junk burning up on re-entry. 

Heat map of the Puget Sound area showing areas where sightings of the meteor were reported (warmer colours indicate more sightings), and the apparent path of the object (blue arrow). American Meteor Society.

Objects of this size probably enter the Earth's atmosphere several times a year, though unless they do so over populated areas they are unlikely to be noticed. They are officially described as fireballs if they produce a light brighter than the planet Venus. The brightness of a meteor is caused by friction with the Earth's atmosphere, which is typically far greater than that caused by simple falling, due to the initial trajectory of the object. Such objects typically eventually explode in an airburst called by the friction, causing them to vanish as an luminous object. However this is not the end of the story as such explosions result in the production of a number of smaller objects, which fall to the ground under the influence of gravity (which does not cause the luminescence associated with friction-induced heating).

 

These 'dark objects' do not continue along the path of the original bolide, but neither do they fall directly to the ground, but rather follow a course determined by the atmospheric currents (winds) through which the objects pass. Scientists are able to calculate potential trajectories for hypothetical dark objects derived from meteors using data from weather monitoring services.

 

Witness reports can help astronomers to understand these events. If you witness a fireball-type meteor over the US you can report it to the American Meteor Society here. 

 

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Millions of Moon Jellyfish seen in Puget Sound.

The National Oceanic and Atmospheric Administration has reported a vast swarm of Moon Jellyfish, Aurelia sp., in Washington State's Puget Sound. The Jellyfish have been growing in numbers since mid September, in a population boom fuelled by unseasonably warm waters, combined with a high nutrient level in the Sound, which can in turn be traced to high rainfall levels on land, caused by higher evaporation from the warm water. Although the number of Jellyfish in the Sound is startling, there is little cause for concern, as, while Moon Jellyfish can sting, their venom is not generally strong enough to cause a serious health risk to Humans.

Thousands of Moon Jellyfish, Aurelia sp., in the water near the dock of the Orcas Island Yacht Club in Eastsound. Rachel Jitabebe Robert/KomoNews.

Members of the genus Aurelia are inshore Jellyfish found in coastal waters in tropical, subtropical and temperate seas around the world. They are large Jellyfish, reaching a maximum size of about 40 cm in diameter, a slight purplish tinge and four large, horseshoe-shaped gonads. Moon Jellyfish often undergo major blooms in the summer months, due to their tolerance for low oxygen conditions, which are harmful to most of their competitors and predators (Fish and large invertebrates), enabling them to dominate environments where these animals are excluded. This tends to lead to summer blooms in enclosed areas (heat and lack of exchange with the open ocean can rapidly deplete oxygen levels), which can be worse in areas where pollution from agriculture or other Human activities leads to eutrophication (excess nutrients which can lead to eutrophication and the rapid growth of blooms of Algae, Bacteria or other micro-organisms, which absorb oxygen from the water leading Fish and other aquatic organisms to asphyxiate). 

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Late Pleistocene lithic artefacts from the Bear Creek Site on the Puget Sound.

The earliest Human settlers are thought to have entered the Americas across the Bering Straits during the last glaciation when sea levels were much lower than today, spreading across the Americas during the Late Pleistocene and early Holocene. Several tool making cultures are known from across the Americas during this time interval. However the Pacific Northwest of North America, where these cultures are thought likely to share a common root, is notoriously lacking in archaeological sites from this era, and those that are known are mostly problematic to date.

In a paper published in the journal PaleoAmerica in January 2015, Robert Kopperl, Amanda Taylor and Christian Miss of SWCA Environmental Consultants, Kenneth Ames of the Anthropology Department at Portland State University and Charles Hodges of Pacific Geoarchaeological Services describe the newly discovered Bear Creek archaeological site (site 45KI839) at Redmond on the western Washington Puget Lowland in Washington State, which has yielded a variety of stone tools from the Late Pleistocene-Holocene transition.

Location of the Bear Creek site (45KI839) near the north shore of Lake Sammamish, Puget Lowland, Washington. Kopperl et al. (2015).

The site was first identified in 2008 when scattered lithic artefacts were found above a layer of tephra and peat. Excavations in 2009  and 2013 revealed a distinctive horizon, identified as Stratum Vc, which yielded a high number of lithic artefacts, including bifaces, scrapers, gravers, projectile points, and unifaces, as well as hammerstones and edge-modified flakes and cobbles, made from chert and fine-grained volcanic rock.

Projectile point bases recovered in situ in Stratum Vc from 2009 test excavation (#2009–50 and –181) and 2013 data recovery (#2013–1156). Kopperl et al. (2015).

Stratum Vc lies on top of a layer of glacial sediments, Stratum VI, and is overlain by a layer of peaty wetland deposits, Stratum Vb and then a layer of Diatomaceous Earth, Stratum II. This is consistent with a warming climate at the end of the Pleistocene, with the glacial deposits formed in a glacial setting, then replaced by wetlands and a lake (Diatomaceous Earth is formed by freshwater Diatoms, a form of single-celled Algae, settling out of the water column far enough from shore to that other sediments are not being laid down). The entire assemblage is cut through by an erosional sandy channel deposit, Stratum III, which also contains some lithic artefacts, apparently reworked in nature.

Schematic profile of stratigraphy across the Bear Creek site (45KI839). Primary in situ artifact-bearing LPH deposit is Stratum Vc, shown in red. Kopperl et al. (2015).

The artefacts show a mixture of traits associated with the Palaeoindian Period (roughly from 18 000 to 8000 BC) and Palaeoarchaic Period (roughly from 8000 to 6000 BC), suggesting that they may date from close to the Pleistocene-Holocene boundary (about 10 000 BC). Importantly it was possible to obtain Radiocarbon Dates from several pieces of carbonized and uncarbonized wood and peat samples within the sequence, including a piece of carbonized wood from within Stratum Vc, dated to 12 770-12 596 years before the present, suggesting that the site may date from the Younger Dryas Period (a short burst of cooling and return to glacial conditions during the thaw at the end of the last glaciation), though a single carbon date is not generally considered absolutely reliable. The clay layer at the base of Stratum Vc has yielded two pieces of uncarbonized Willow wood, which yielded dates of 12 597-12 116 and 12 690-12 420 years before the present – this is actually slightly younger than the date from Stratum Vc, suggesting that it may be inaccurate, but still within the Younger Dryas. Stratum Vb has produced a range of dates, ranging from 10 586-10 298 to 8543-8376, i.e. the very latest Pleistocene and Early Holocene.

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Bone infection in a Pre-Columbian skull from south Jamaica.

The Taíno people are thought to have colonized the Caribbean Islands by island hopping from northern South America from about 500 BC onwards, reaching Jamaica by around 645-898 AD. They were skilled agriculturalists, introducing crops such as Cassava and Maize from South America and changing...

Pleistocene rock carving from Brazil; possibly the oldest art in the Americas.

The earliest people arrived in the Americas some time between 12 000 and 13 500 years ago. They are known from burials and tools scattered (albeit thinly) across both North and South America. Art made by these...

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Magnitude 3.0 Earthquake in Washington State.

The United States Geological Survey recorded a Magnitude 3.0 Earthquake at a depth of 27 km, 2 km to the north of Indianola, on Puget Sound opposite Seattle, slightly before 0.10 am local time (slightly before 7.10 am GMT) on Thursday 5 September 2013. This is not a large quake, and no damage or injuries have been reported, but it was felt over a fairly wide area.

The approximate location of the 5 September 2013 Indianola Earthquake. Google Maps.

Washington State is located on the western margin of the North American Plate, to the west the Juan de Fuca Plate is being subducted along the Cascadia Subduction Zone, passing under Washington State as it sinks into the Earth. This is not a smooth process, and the two plates frequently stick together then break apart again as the pressure builds up, causing Earthquakes in the process. 

The heat and pressure within the Earth also slowly melts the subducting plate, liquifying more volatile minerals which then rise through the overlying North American Plate as magma, fueling the volcanoes of America's Pacific Northwest.

Witness accounts of quakes can help geologists to understand these events and the rock structures that cause them. If you felt this quake (or if you wee in the area but did not, which is also useful information) you can report it to the USGS here.

See also Magnitude 6.2 Earthquake of the coast of British Columbia, Magnitude 3.6 Earthquake in Washington State, Magnitude 5.3 Earthquake shakes Vancouver Island, Magnitude 4.3 Earthquake in central Washington State and Scientists predict eruption of Axial Seamount.

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Major landslip on Whidbey Island, Washington State.

A major landslip occurred on Whidbey Island, Washington State, at about 4.15 am local time (about 11.15 am GMT) on Wednesday 27 March 2013. Severely damaging one home and destroying a section of road that cut of twenty more. The twenty isolated homes and a further seventeen judged to be potentially unsafe by Central Whidbey Island Fire and Rescue were evacuated. No injuries have been reported, and only twelve people were reported to have been evacuated during the incident, as many properties in the area are holiday homes only inhabited seasonally.

House damaged by the 27 March landslip on Whidbey Island. Though apparently structurally sound this property has more-or-less totally lost its foundations, making it unlikely it can be saved. KING 5/Reuters.

Whidbey Island is notoriously prone to such erosional landslip events. Much of the island is made up of unconsolidated glacial deposits, held together with dried clay rather than lithified by mineral deposits. Such deposits can quickly become waterlogged following heavy rainfall (something Washington State is famed for) and lose all cohesion. The United States Geological Survey estimates that 51% of the coastline of Whidbey Island is at risk from such collapses.

Aerial photograph of part of the landslip on Whidbey Island. Associated Press.

See also Woman dies as house destroyed by landslip in Looe, Cornwall, At least six killed by West Java landslide, Landslip at Bowleaze Cove, Dorset, Monmouth Beach, Lyme, closed due to danger of landslips and Woman killed by rockfall on Dorset Beach.

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