Thursday, March 31, 2016

[Geology2] Popo pops off at night (video)





__._,_.___
Posted by: Lin Kerns <linkerns@gmail.com>



__,_._,___
Posted by at No comments:

[Geology2] One of the best pages on volcanoes





__._,_.___
Posted by: Lin Kerns <linkerns@gmail.com>



__,_._,___
Posted by at No comments:

Re: [Geology2] Unraveling a geological mystery using lasers from space



MIght too much info.. lol. We also have a great bike trail called appropriately enough, The Drumlin Bike Trail....Allison



On Wednesday, March 30, 2016 12:33 PM, "'allison.ann@att.net' allison.ann@att.net [geology2]" <geology2@yahoogroups.com> wrote:


 
We have drumlin hills around here. I will see if I can find some pics for you..Allison

Sent from my Sprint phone.

----- Reply message -----
From: "coyote coyote2@ymail.com [geology2]" <geology2@yahoogroups.com>
To: "geology2@yahoogroups.com" <geology2@yahoogroups.com>
Subject: [Geology2] Unraveling a geological mystery using lasers from space
Date: Wed, Mar 30, 2016 11:32 AM

 
Even after taking a look at the linked Abstract (which was too technical for this amateur), I'm not sure I (or the writer of that news article) understand the mechanism. 

Are they like moraines of the ice-streams, so forming (not at sides of the glacier) but at the sides of the ice-streams?

I'm not sure I've spent enough time in that part of the country to see a Drumlin.


From: "Lin Kerns linkerns@gmail.com [geology2]" <geology2@yahoogroups.com>
To: Geology2 <geology2@yahoogroups.com>
Sent: Wednesday, March 30, 2016 8:22 AM
Subject: [Geology2] Unraveling a geological mystery using lasers from space

 

Unraveling a geological mystery using lasers from space

Date:
March 29, 2016
Source:
University of Toronto
Summary:
Drumlins and megaridges are all part of a single family of landforms formed by erosion, new research concludes. Shaped like an upturned boat, drumlin hills are found clustered together in their hundreds and thousands in distinct fields called swarms. They are the most common landform across large areas of northern North America and Europe, marking the footprint of great sheets that formed during past ice ages.
alt
Shaped like an upturned boat, drumlin hills (pictured above) are found clustered together in their hundreds and thousands in distinct fields called swarms. They're the most common landform across large areas of northern North America and Europe, marking the footprint of massive ice sheets that formed during past ice ages.
Credit: University of Toronto Scarborough
It's a mystery that has stumped geologists for more than a century.
Now, thanks to new technology -- including satellite laser imagery -- researchers may be one step closer to understanding the origins of an archetypal landform: the drumlin hill.
"Drumlin hills are the most studied and yet the most enigmatic ice age landform," says U of T Scarborough geology professor Nick Eyles. "Thanks to high resolution satellite imagery and new technology like LiDAR, we're literally seeing the surface of the planet for the first time and finding major surprises in the process."
Shaped like an upturned boat, drumlin hills are found clustered together in their hundreds and thousands in distinct fields called swarms. They are the most common landform across large areas of northern North America and Europe, marking the footprint of great sheets that formed during past ice ages.
The question that's stumped geologists since drumlins were first studied more than 150 years ago is whether they were built up progressively or sculpted out of older sediment. Eyles and his team including PhD candidate Shane Sookhan and undergraduate student Lina Arbelaez-Moreno were able to determine that drumlins are simply streamlined "islands" of sediment that are often bisected to form kilometre-long skinny megaridges. Their research, published in the journal Sedimentary Geology, suggests that drumlins and megaridges are all part of a single family of landforms formed by erosion.
"The new data we were able to obtain shows that these landforms occur on hard rock, which stresses the importance of sculpting below the base of the ice sheet," says Arbelaez-Moreno.
To illustrate the importance of megaridges Eyles points to research being done on the modern Greenland and Antarctica ice sheets. These are slow moving ice sheets but contain faster flowing corridors called 'ice streams' that are up to tens of kilometres wide, hundreds of kilometres in length and can move as fast as 1 km annually.
"They're essentially arteries moving huge volumes of ice toward the margin of the ice sheet," explains Eyles. The thinning and retreating of modern ice streams in a warming world has exposed their underlying beds which are seen to be megaridged, and that appears to allow the ice to flow faster across its bed by creating a slippery low-friction surface, he adds.
The last Canadian ice sheet (Laurentide) was as much as 3 km thick and behaved in exactly the same way, says Eyles. "The transition from drumlins to megaridges may record the final gasp of the ice sheet as it warmed up and began to stream over its bed."
Debris that is being dragged under these streams is highly erosive -- "think of sandpaper'' says Sookhan -- and the process sculpts the underlying surface, allowing drumlins to be progressively whittled down into longer and longer megaridges.
The data used by the researchers relied on high resolution satellite imagery and new technologies including LiDAR, which uses hundreds of laser beams fired from planes onto the land below. The result is the creation of highly accurate topographic maps even where landscapes are covered by trees or water.
"We still have a lot to learn about how drumlins are formed, but this imaging technique has changed the science by providing a new way of looking at glacial landscapes," says Sookhan.
The megaridges identified by Eyles and his team are particularly common around Peterborough, Ontario at the site of one of the most easily accessible drumlin fields in Canada.
"You could say drumlins are quintessentially Canadian," says Eyles. "They do occur in Europe, but are far more common here because almost the entire country was covered by the Laurentide Ice Sheet during the last ice age."
Story Source:
The above post is reprinted from materials provided by University of Toronto. Note: Materials may be edited for content and length.
Journal Reference:
  1. Nick Eyles, Niko Putkinen, Shane Sookhan, Lina Arbelaez-Moreno. Erosional origin of drumlins and megaridges. Sedimentary Geology, 2016; DOI: 10.1016/j.sedgeo.2016.01.006

University of Toronto. "Unraveling a geological mystery using lasers from space." ScienceDaily. ScienceDaily, 29 March 2016. <www.sciencedaily.com/releases/2016/03/160329112849.htm>.

--






__._,_.___
Posted by: Allison Maricelli-Loukanis <allison.ann@att.net>



__,_._,___
Posted by at No comments:

[californiadisasters] Volunteer Reception Center Operations Video



Just In Time Disaster Training Library

Volunteer Reception Center Operations Video

 

The Just In Time Disaster Training Library has added a new video regarding Volunteer Reception Center Operations.

 

The video outlines the procedures for processing spontaneous un-affiliated volunteers through the four stations of a Volunteer Reception Center. 

 

With over 1,900 disaster mitigation, preparedness, response and recovery training videos the library is the most comprehensive, easy to search, FREE internet based source for training curriculum for today’s emergency responders.

 

The library can be accessed at the following web site:

 

www.JustInTimeDisasterTraining.org

 

Join the Just In Time Disaster Training Library's Twitter and Facebook.

 

 



__._,_.___
Posted by: "Chris Floyd" <floydchris@aol.com>


Be sure to check out our Links Section at http://groups.yahoo.com/group/californiadisasters/links
Please join our Discussion Group at http://groups.yahoo.com/group/californiadisasters_discussion/ for topical but extended discussions started here or for less topical but nonetheless relevant messages.




__,_._,___
Posted by at No comments:

[californiadisasters] On This Date In California Weather History (March 31)



2013: This was the second day of stormy weather for the Easter weekend (that started on March 30th). 
A strong upper-level low pressure system moved over the region and brought numerous showers and thunderstorms to the region, including the central San Joaquin Valley and southern Sierra Nevada, as well as the adjacent foothills. 
Almost 2,000 lightning strikes were reported during the late afternoon and evening hours throughout the Hanford warning and forecast area. 
Pea-sized (about one quarter inch in diameter) hail was reported in Los Banos, although it covered much of the ground about one or two inches deep. 
Some hail as much as one inch in diameter (or quarter-sized), was reported along Highway 99, about 10 miles southeast of Madera; this storm briefly snarled traffic. 
A storm spotter photographed an impressive looking thunderstorm with supercell
characteristics, including a wall cloud and flanking clouds associated with its updraft, moved over Millerton Lake around 8:30 to 9:00 PM local time. 
However, no damage was reported with this storm.

1999: Snowburst in 8 hours dropped 11" of snow at Tuolumne Meadows, 6" at Mariposa and 4" at Oakhurst.

1998: During a period starting on this day and ending on 4.1, numerous funnel clouds were reported near the coast of Orange and San Diego Counties, two of which became waterspouts off Orange County.
One waterspout briefly hit the coast as a tornado south of the Huntington Beach Pier.

1997: A strong cold front moving through the Kern County mountains caused gusts to 81 mph at Mojave.

1989: It was 101° F in Borrego Springs, the highest temperature on record for March.
This also occurred on 3.27.1988.

1982: 29" of snow fell at Glenbrook, NV (east shore Lake Tahoe).

1966: It was 82° F in Palomar Mountain and 104° F in Palm Springs, each the highest temperature on record for March.

1966: Pinnacles reported a high of 93° F. 

1936: 14" of snow fell at Cedarville (Surprise Valley).

1916: Yosemite Valley reached 90° F, warmest high on temperature on record so early in the season.

Source: NWS San Francisco/Monterey, Hanford, Reno, & San Diego

--

This email has been sent from a virus-free computer protected by Avast. www.avast.com


__._,_.___
Posted by: Kim Noyes <kimnoyes@gmail.com>


Be sure to check out our Links Section at http://groups.yahoo.com/group/californiadisasters/links
Please join our Discussion Group at http://groups.yahoo.com/group/californiadisasters_discussion/ for topical but extended discussions started here or for less topical but nonetheless relevant messages.




__,_._,___
Posted by at No comments:

[Geology2] How many dinosaurs were there?



How many dinosaurs were there?



There are more than 10,000 species of bird living on Earth today. If you recognise that birds are living dinosaurs, which overwhelming evidence indicates that they are, then this makes them more diverse than their living mammalian counterparts. So if you take the number of species to mean anything, this means we're still in the reign of the dinosaurs! These days they're just mostly a bit smaller and fluffier than their Mesozoic ancestors.

But one massive question still remains for Palaeontologists and Neontologists: Why are there so many bird species around today, when we have relatively so few dinosaurs in the fossil record? This disparity is even more extreme when you consider that while non-avian dinosaurs were around for about 170 million years, there were only ever about 800 or so species of dinosaur, based on current records. The actual number fluctuates through time, as new species are discovered, and others are shown to be invalid through research broadly known as 'taxonomy'.

Recently, Jostein Starfelt and Lee Hsiang Liow of the University of Oslo made a major step forward in answering one of the key questions related to this: Just how many dinosaur species were there in reality?

Most previous studies of dinosaur diversity have only looked at relative diversity, which assess proportional changes from one time to another. But how do you actually estimate the real total number of dinosaurs through time?

How do Palaeontologists read the fossil record?

One of the major problems in calculating diversity is that the fossil record is a poor representation of the biological part of ecosystems. Animals are preserved differently due to differences in their anatomy. Also, not all animals have the same chance of becoming fossils, based on where they happen to find their final resting place.

Furthermore, the geological record is preserved differently through space and time, due to where seas and rivers were to deposit sediment, and due to processes of mountain building and erosion.

Once you get past these two hurdles, humans have then sampled this record differently through time, for example by collecting only from rocks where they know there is a high probability of finding new fossils, also known as the 'bonanza effect'.

Dinosaurs be TRiPSin'..

All of this variation is broadly known as sampling bias. While many methods have been developed to account for these biases in different ways, Starrfelt and Liow developed a brand new one called TRiPS, which stands for True Richness estimated using a Poisson Sampling Model. This accounts for variation in the sampling of the dinosaur record by estimating both the bias and the overall diversity (richness) based on variation in the number of times each dinosaur species occurs at different points in time. For example, if we know lots of specimens of a particular dinosaur species, we can infer that it has a relatively high preservation potential and collection probability. The authors used this to investigate the dynamics of dinosaur diversity through time, and to assess possible extinction events in their history.

Using this new method, applied to the whole known dinosaur record through the whole of the Mesozoic (Triassic to the end of the Cretaceous), they estimated that 1543-2468 species existed altogether around the globe. While the authors acknowledge that this is a crude estimate, it is largely convergent on previous calculations too.

Importantly, this number is much higher than what is currently known from the fossil record. If you break this down into the three major dinosaur groups, a slightly different pattern emerges. Theropods, the mostly carnivorous group leading to modern birds, had almost twice as many species (1115) than either the long-necked sauropods (513) or bird-hipped ornithischians (508).

Steve Brusatte of the University of Edinburgh is sceptical though: "I would take these numbers with an ocean full of salt", he said. "There are over 10,000 species of birds – living dinosaurs – around today. So saying there were only a few thousand dinosaur species that lived during 150+ million years of the Mesozoic doesn't pass the sniff test. That's not the fault of the authors. They've employed advanced statistical methods that take the data as far as it can go. The problem is the data. The fossil record is horrifically biased. Only a tiny fraction of all living things will ever be preserved as fossils. So what we find is a very biased sample of all dinosaurs that ever lived, and no amount of statistical finagling can get around that simple unfortunate truth."

Jostein Starrfelt also thinks that there is more work to be done in this domain: "Our estimate of total dinosaur richness of approximately 2000 species was done attempting to combine the sampling probabilities from all stages of the Mesozoic and should be interpreted with caution, and my gut feeling is that the total number of dinosaur species for the whole Mesozoic is higher than our total estimate suggests."

The future of dinosaur hunting

So what does all of this mean for dinosaur hunters? Well, it suggests that there are still hundreds more to be found out there! So get your hiking boots out and go track some dinosaurs!

Brusatte said "There are huge swaths of the planet and huge stretches of the Mesozoic that have yielded few or no dinosaur fossils. The Middle Jurassic and mid Cretaceous are notoriously poorly sampled, as are Antarctica, Australia, and much of Africa. It's only been over the last few decades that we've come to appreciate the bounty of Chinese dinosaurs, and they keep coming at a furious pace. We still have a lot to find." Indeed, Starrfelt agreed that their method could be used to "get a better picture of which continents are under-sampled and for which periods (and could thus deserve some more human effort)."

It also hints that there might be something fundamentally different about the evolutionary biology of bird-line dinosaurs, and non-avian dinosaurs. Many studies are beginning to unravel the origins and diversification of modern birds, but these will only truly shed light if they are considered in the wider context of dinosaur diversity through time.

Starrfelt also hinted at his future plans with this line of research. "As with most scientific endeavours I wouldn't say that TRiPS has solved the major problems of using the fossil record as a source of information about the dynamics of clades; but that it might be a good start. The approach lends itself easily to being extended; in the future we might be able to include information about the 'human effort' part of fossil bias by interpreting the sampling rate as the product of a fossilization rate and a 'discovery probability', for instance. We're also in the process of putting TRiPS in a Bayesian framework." How exciting!

Only by being able to estimate diversity with greater accuracy through space and time can we begin to understand the forces that have shaped the evolutionary history of animals.

So many birdies! (Source)

Reference:
Jostein Starrfelt et al. How many dinosaur species were there? Fossil bias and true richness estimated using a Poisson sampling model, Philosophical Transactions of the Royal Society B: Biological Sciences (2016). DOI: 10.1098/rstb.2015.0219

http://www.geologypage.com/2016/03/how-many-dinosaurs-were-there.html

--


__._,_.___
Posted by: Lin Kerns <linkerns@gmail.com>



__,_._,___
Posted by at No comments:

[Geology2] Scientists explain evolution of some of the largest dinosaurs



Scientists explain evolution of some of the largest dinosaurs

Date:
March 30, 2016
Source:
University of Liverpool
Summary:
Scientists have developed computer models of the bodies of sauropod dinosaurs to examine the evolution of their body shape.
This is a Giraffatitan model of a Sauropod.
Credit: Dr Peter L Falkingham (Liverpool John Moores University)

Scientists from the University of Liverpool have developed computer models of the bodies of sauropod dinosaurs to examine the evolution of their body shape.

Sauropod dinosaurs include the largest land animals to have ever lived. Some of the more well-known sauropods include Diplodocus, Apatosaurus and Brontosaurus. They are renowned for their extremely long necks, long tails as well as four thick, pillar-like legs and small heads in relation to their body.

To date, however, there have been only limited attempts to examine how this unique body-plan evolved and how it might be related to their gigantic body size. Dr Karl Bates from the University's Department of Musculoskeletal Biology and his colleagues used three-dimensional computer models reconstructing the bodies of sauropod dinosaurs to analyse how their size, shape and weight-distribution evolved over time.

Evolutionary history

Dr Bates found evidence that changes in body shape coincided with major events in sauropod evolutionary history such as the rise of the titanosaurs. The early dinosaurs that sauropods evolved from were small and walked on two legs, with long tails, small chests and small forelimbs. The team estimate that this body shape concentrated their weight close to the hip joint, which would have helped them balance while walking bipedally on their hind legs.

As sauropods evolved they gradually altered both their size and shape from this ancestral template, becoming not only significantly larger and heavier, but also gaining a proportionally larger chest, forelimbs and in particular a dramatically larger neck.

The team's findings show that these changes altered sauropods' weight distribution as they grew in size, gradually shifting from being tail-heavy, two-legged animals to being front-heavy, four-legged animals, such as the large, fully quadrupedal Jurassic sauropods Diplodocus and Apatosaurus.

The team found that these linked trends in size, body shape and weight distribution did not end with the evolution of fully quadrupedal sauropods. In the Cretaceous period -- the last of the three ages of the dinosaurs -- many earlier sauropod groups dwindled. In their place, a new and extremely large type of sauropod known as titanosaurs evolved, including the truly massive Argentinosaurus and Dreadnoughtus, among the largest known animals ever to have lived.

Front heavy

The team's computer models suggest that in addition to their size, the titanosaurs evolved the most extreme 'front heavy' body shape of all sauropods, as a result of their extremely long necks.

Dr Bates said: "As a result of devising these models we were able to ascertain that the relative size of sauropods' necks increased gradually over time, leading to animals that were increasingly more front-heavy relative to their ancestors."

Dr Philip Mannion from Imperial College London, a collaborator in the research, added: "These innovations in body shape might have been key to the success of titanosaurs, which were the only sauropod dinosaurs to survive until the end-Cretaceous mass extinction, 66 million years ago."

Dr Vivian Allen from the Royal Veterinary College London, who also collaborated in the research, added: "What's important to remember about studies like this is that there is a very high degree of uncertainty about exactly how these animals were put together. While we have good skeletons for many of them, it's difficult to be sure how much meat there was around each of the bones. We have built this uncertainly into our models, ranging each body part from emaciated to borderline obesity, and even using these extremes we still find these solid, trending changes in body proportions over sauropod evolution."

Story Source:

The above post is reprinted from materials provided by University of Liverpool. Note: Materials may be edited for content and length.

Journal Reference:

  1. Karl T. Bates, Philip D. Mannion, Peter L. Falkingham, Stephen L. Brusatte, John R. Hutchinson, Alejandro Otero, William I. Sellers, Corwin Sullivan, Kent A. Stevens, Vivian Allen. Temporal and phylogenetic evolution of the sauropod dinosaur body plan. Royal Society Open Science, 2016; 3 (3): 150636 DOI: 10.1098/rsos.150636

University of Liverpool. "Scientists explain evolution of some of the largest dinosaurs." ScienceDaily. ScienceDaily, 30 March 2016. <www.sciencedaily.com/releases/2016/03/160330085622.htm>.

--


__._,_.___
Posted by: Lin Kerns <linkerns@gmail.com>



__,_._,___
Posted by at No comments:

[Geology2] Fracking -- not wastewater disposal -- linked to most induced earthquakes in Western Canada



Fracking -- not wastewater disposal -- linked to most induced earthquakes in Western Canada

Date:
March 29, 2016
Source:
Seismological Society of America
Summary:
A survey of a major oil and natural gas-producing region in Western Canada suggests a link between hydraulic fracturing or 'fracking' and induced earthquakes in the region.

A survey of a major oil and natural gas-producing region in Western Canada suggests a link between hydraulic fracturing or "fracking" and induced earthquakes in the region, according to a new report published online in the journal Seismological Research Letters.

The study's findings differ from those reported from oil and gas fields in the central United States, where fracking is not considered to be the main cause of a sharp rise in induced seismicity in the region. Instead, the proliferation of hundreds of small earthquakes in that part of the U.S. is thought to be caused primarily by massive amounts of wastewater injected back into the ground after oil and gas recovery.

The SRL study does not examine why induced seismicity would be linked to different processes in the central U.S. and western Canada. However, some oil and gas fields in the U.S., especially Oklahoma, use "very large amounts of water" in their operations, leading to much more wastewater disposal than in Canadian operations, said Gail M. Atkinson of Western University.

It is possible that massive wastewater disposal in the U.S. is "masking another signal" of induced seismicity caused by fracking, Atkinson said. "So we're not entirely sure that there isn't more seismicity in the central U.S. from hydraulic fracturing than is widely recognized."

The fracking process uses high-pressure injections of fluid to break apart rock and release trapped oil and natural gas. Both fracking and wastewater injections can increase the fluid pressure in the natural pores and fractures in rock, or change the state of stress on existing faults, to produce earthquakes.

The Western Canada Sedimentary Basin (WCSB) contains one of the world's largest oil and gas reserves, and is dotted with thousands of fracking wells drilled in multi-stage horizontal operations. Atkinson and her colleagues compared the relationship of 12,289 fracking wells and 1236 wastewater disposal wells to magnitude 3 or larger earthquakes in an area of 454,000 square kilometers near the border between Alberta and British Columbia, between 1985 and 2015.

The researchers performed statistical analyses to determine which earthquakes were most likely to be related to hydraulic fracturing, given their location and timing. The analyses identified earthquakes as being related to fracking if they took place close to a well and within a time window spanning the start of fracking to three months after its completion, and if other causes, such as wastewater disposal, were not involved.

Atkinson and colleagues found 39 hydraulic fracturing wells (0.3% of the total of fracking wells studied), and 17 wastewater disposal wells (1% of the disposal wells studied) that could be linked to earthquakes of magnitude 3 or larger.

While these percentages sound small, Atkinson pointed out that thousands of hydraulic fracturing wells are being drilled every year in the WCSB, increasing the likelihood of earthquake activity. "We haven't had a large earthquake near vulnerable infrastructure yet," she said, "but I think it's really just a matter of time before we start seeing damage coming out of this."

The study also confirmed that in the last few years nearly all the region's overall seismicity of magnitude 3 or larger has been induced by human activity. More than 60% of these quakes are linked to hydraulic fracture, about 30-35% come from disposal wells, and only 5 to 10% of the earthquakes have a natural tectonic origin, Atkinson said.

Atkinson said the new numbers could be used to recalculate the seismic hazard for the region, which could impact everything from building codes to safety assessments of critical infrastructure such as dams and bridges. "Everything has been designed and assessed in terms of earthquake hazard in the past, considering the natural hazard," she said. "And now we've fundamentally changed that, and so our seismic hazard picture has changed."

The researchers were also surprised to find that their data showed no relationship between the volume of fluid injected at a hydraulic fracturing well site and the maximum magnitude of its induced earthquake.

"It had previously been believed that hydraulic fracturing couldn't trigger larger earthquakes because the fluid volumes were so small compared to that of a disposal well," Atkinson explained. "But if there isn't any relationship between the maximum magnitude and the fluid disposal, then potentially one could trigger larger events if the fluid pressures find their way to a suitably stressed fault."

Atkinson and her colleagues hope to refine their analyses to include other variables, such as information about extraction processes and the geology at individual well sites, "to help us understand why some areas seem much more prone to induced seismicity than others."

The scientists say the seismic risks associated with hydraulic fracturing could increase as oil and gas companies expand fracking's use in developing countries, which often contain dense populations and earthquake-vulnerable infrastructure.

 

Story Source:

The above post is reprinted from materials provided by Seismological Society of America. Note: Materials may be edited for content and length.

Journal Reference:

  1. Gail M. Atkinson, David W. Eaton, Hadi Ghofrani, Dan Walker, Burns Cheadle, Ryan Schultz, Robert Shcherbakov, Kristy Tiampo, Jeff Gu, Rebecca M. Harrington, Yajing Liu, Mirko van der Baan, and Honn Kao. Hydraulic Fracturing and Seismicity in the Western Canada Sedimentary Basin. Seismological Research Letters, May/June 2016 DOI: 10.1785/0220150263
Seismological Society of America. "Fracking -- not wastewater disposal -- linked to most induced earthquakes in Western Canada." ScienceDaily. ScienceDaily, 29 March 2016. <www.sciencedaily.com/releases/2016/03/160329132238.htm>.

--


__._,_.___
Posted by: Lin Kerns <linkerns@gmail.com>



__,_._,___
Posted by at No comments:
Newer Posts Older Posts Home
Subscribe to: Posts (Atom)