California Should Have Had a Major Earthquake

California Should Have Had a Major Earthquake by Now, Geologists Warn

There have been no major ground rupturing earthquakes along California's three highest slip rate faults in the past 100 years. A new study published in Seismological Research Letters concludes that this current "hiatus" has no precedent in the past 1000 years.

U.S. Geological Survey researchers Glenn Biasi and Kate Scharer analyzed long paleoseismic records from the San Andreas, San Jacinto and Hayward Faults for the past 1000 years, to determine how likely it might be to have a 100-year gap in earthquakes across the three faults. They found that the gap was very unlikely -- along the lines of a 0.3% chance of occurring, given the seismic record of the past 1000 years.

The results emphasize that the hiatus is exceptional, and that the gap isn't some sort of statistical fluke created by incomplete paleoseismic records, said Biasi.

The analysis also indicates that the next 100 years of California earthquakes along these faults could be a busy one, he noted. "If our work is correct, the next century isn't going to be like the last one, but could be more like the century that ended in 1918."

Between 1800 and 1918, there were eight large ground-rupturing earthquakes along the faults, including the well-known 1906 earthquake in San Francisco and the similar-sized 1857 rupture of the San Andreas in southern California, but nothing so large since.

"We know these big faults have to carry most of the [tectonic] motion in California, and sooner or later they have to slip," said Biasi. "The only questions are how they're going to let go and when."

The three faults and their major branches analyzed by the researchers accommodate the majority of the slip between the Pacific and North American plate boundary. Paleoseismic records from the faults predict that there would be three to four large ground-rupturing earthquakes (magnitude 6.5 or larger) each century.

Biasi and Scharer examined the best available paleoseismic records from sites along the three faults to determine whether the current gap could be explained by missing data, or incorrect radiocarbon dating of past earthquakes. From these data, they calculated the probability that there would be a 100-year gap in ground-rupturing earthquakes across all three faults.

"Our paper confirms that this hiatus is very improbable and it's our view that our efforts will be better spent considering explanations for this, rather than trying to bend the data to make the hiatus a 'statistically improbable but could happen' kind of thing," said Biasi.

"We're saying, no, it's not a data problem, it's not a data choice problem, it doesn't matter how you slice this," he added. "We just have not had earthquakes that past records predict that we should have had."

He likened the hiatus to what a person might see if they pulled up a chair alongside a freeway to count passing cars. "You might say that a certain number of cars per hour is kind of representative, and then something happens and you go ten minutes of seeing no cars. If it's just ten minutes, you could say it was a statistical fluke."

But if the freeway stays clear of traffic for a long time, "the other reason there might be no cars is that up around the bend, there's a wreck," said Biasi.

The researchers would like more seismologists to focus on the reasons -- "the wreck around the bend" -- behind the current hiatus.

"We had the flurry of very large earthquakes from 1800 to 1918," Biasi said. "It's possible that among them they just wrung out -- in the sense of wringing out a dishrag -- a tremendous amount of energy out the system."

There may be stronger long-range interactions between the faults than suspected, or there may be unknown features of the mantle and lower crust below the faults that affect the probability of ground-rupturing earthquakes, he noted.


The above story is based on Materials provided by Seismological Society of America. and by Senior Geologist Prof. Dr. Faisal Umer from U.E.T, PAK in collaboration with prof. Shazab Ali from Oxford University, UK.

Places Where You Can Go to Dig Gemstones

North Carolina: Places Where You Can Go TO Dig For Gemstones in NC

Gem materials found in North Carolina include Amarine, beryl, citrine, emerald, garnet, moonstone, rose quartz, ruby, sapphire, smoky quartz, staurolite, topaz, tourmaline, and many others.

Members of the North Carolina Legislature declared Emerald the state's official gemstone.

Gem Mountain

Gem Mountain is located in Spruce Pine, North Carolina in the heart of the Spruce Pine Mining District. They operate several mines in the area and offer mining at the flume line where you go through buckets of material or you can take a trip out to a mine and dig your own. They have the Brushy Creek Mine where you can dig for aquamarine, garnet, golden beryl, tourmaline, smoky quartz and clear quartz. It is a relatively new mine and has been very successful. You can also take a trip out to the legendary Hoot Owl Mine. This mine has been around for a 100+ years. It is a very impressive mine to see. These trips are 4 hour trips and transportation, tools and a guide are provided. The cost is $75 for adults and $35 for children 11 and under. Free stone identification is provided and lapidary and jewelry making services are available.

Address: 13780 NC-226, Spruce Pine, NC 28777

Hiddenite Gem Mines

Famously popular, Hiddenite Gem Mines is known for the discovery of some of the largest gems in the world. Comprised of several mines, Hiddenite Gem Mine’s group includes Emerald Hollow Mine—which is open for public mining—Adams Mine and NAEM (North American Emerald Mine). At this Great Smoky Mountain-area mine in Franklin, North Carolina, about 60 miles southwest of Blowing Rock, you might find rubies, sapphires, garnets, and rutile. Your admission fee gets you two buckets, a screen box, and a seat cushion, which you use at the flume line. For a dollar extra, you can get a shade umbrella. Admission: $15 for ages 12 and up, $10 for kids 6 to 11; free for ages 5 and under.

Address: 484 Emerald Hollow Mine Dr, Hiddenite, NC 28636 

Elijah Mountain Gem Mine

At Elijah Mountain Gem Mine, in Hendersonville, NC, you become a prospector from the 1800's and mine for real gem stones that you can keep! Gems that are found daily include Rubys, Sapphires, Emeralds, Quartz crystals, Citrine, Amethyst, Garnets, Adventurine, Sodalite, Opal, Fluorite, Aquamarine and many more! During colder months they have INDOOR mining too!

Address: 2120 Brevard Rd, Hendersonville, NC 28739

Foggy Mountain Gem Mine

Foggy Mountain Gem Mine has been family owned and operated for generations. They are located in the mountain community of Boone. For an affordable, fun and educational adventure for all ages.

Address: 4416 NC HWY 105 S, Boone, NC 28607

Foggy Mountain Gem Mine

At Asheville Biltmore Gem Mine is rock hounds and treasure hunters of all ages love to find the treasures of the earth. Emeralds, sapphires, rubies, aquamarine, tourmaline, garnet, amethyst, citrine, smoky quartz, topaz, and many others are waiting to be discovered!, and you can view stones being cut and enjoy indoor winter gem mining.
Address: 1997 Hendersonville Rd, Asheville, NC 28803

Emerald Village

Emerald Village is a group of gem, mining, and historical attractions nestled deep in the Blue Ridge Mountains of Western North Carolina, just off the Blue Ridge Parkway and within an hour's drive of Asheville, Boone, and Blowing Rock. The McKinney Mines have produced over 100 different rocks, minerals, and gems. Gems are scarce but many rare minerals can be found. You will find nice Mica specimens as well as Smoky Quartz, Feldspar, and Garnets. Aquamarine & Green and Yellow Beryl have been found along with many rare and unusual rocks & minerals, including Columbite, Samarskite, Torbernite, Uranophane, Hyalite Opal, Malachite, Tourmaline, Thulite, Amazonite, Pyrite and Dendrites. Emerald Village is Pet Friendly!
Address: 331 McKinney Mine Road, Spruce Pine, NC 28777

Rose Creek Mine

Operating since 1952, Rose Creek Mine is one of 3 state licensed gem mines in Macon County, North Carolina. Indian Reservation. In Doc's Rocks Gem Mine you can find Ruby, Sapphire, Garnet, Amethyst, Citrine, Moonstone, Topaz, Smoky Quartz, Rose Quartz, Quartz Crystals and more! All equipment is provided and they help beginners. 
Address: 115 Terrace Ridge Dr, Franklin, NC 28734

Chimney Rock Gemstone Mine

Nestled deep in the Hickory Nut Gorge, on the banks of the Rocky Broad River in historic Chimney Rock Village. You are invited to a riverside setting unparalleled by any other mine in the area. Come experience the wonder and excitement of prospecting for gemstones in a pleasant and comfortable atmosphere. The basic process of Flume Mining involves a bucket of mine dirt, and lots of running water. We supply you with all the equipment you need to start your own Flume mining operation for the day. 
Address: 397 Main St, Chimney Rock, NC 28720

See also:
6 Places Where Can You Go to Dig for Gemstones in California
What Is Geyser Opal, and Where You Can Find It?
Dig Your Own Unique Opals From Nevada 
Top Spots For Gem Hunting In The US 
Where to Find Opals in Oregon?

Meteor Blast of Size More Than

Meteor Blast Over Bering Sea was 10 Times Size of Hiroshima

A meteor explosion over the Bering Sea late last year unleashed 10 times as much energy as the atomic bomb that destroyed Hiroshima, scientists have revealed.

The fireball tore across the sky off Russia’s Kamchatka peninsula on 18 December and released energy equivalent to 173 kilotons of TNT. It was the largest air blast since another meteor hurtled into the atmosphere over Chelyabinsk, in Russia’s south-west, six years ago, and the second largest in the past 30 years.

Unlike the Chelyabinsk meteor, which was captured on CCTV, mobile phones and car dashboard cameras, the December arrival from outer space went largely unnoticed at the time because it exploded in such a remote location.

Nasa received information about the blast from the US air force after military satellites detected visible and infrared light from the fireball in December. Lindley Johnson, a planetary defence officer at Nasa, told BBC News that blasts of this size were expected only two or three times a century.

The space agency’s analysis shows that the meteor, probably a few metres wide, barrelled into Earth’s atmosphere at 72,000mph and exploded at an altitude of 16 miles. The blast released about 40% of the energy of the meteor explosion over Chelyabinsk, according to Kelly Fast, Nasa’s near-Earth objects observations programme manager, who spoke at the 50th Lunar and Planetary Science conference near Houston.

Since the event came to light, meteor researchers have been asking airlines for any sightings of the fireball, which came in close to routes used by commercial carriers flying between North America and Asia.

Peter Brown, a meteor specialist at Western University in Canada, spotted the blast independently in measurements made by global monitoring stations. The explosion left its mark in data recorded by a network of sensors that detect infrasound, which has a frequency too low for the human ear to pick up. The network was set up to detect covert nuclear bomb tests.

The Bering Sea event is another reminder that despite efforts to identify and track space rocks that could pose a threat to Earth, sizeable meteors can still arrive without warning. Nasa is working to identify 90% of near-Earth asteroids larger than 140 metres by 2020, but the task could take another 30 years to complete.

The 20m-wide meteor that detonated over Chelyabinsk lit up the morning sky on 15 February 2013. At its most intense, the fireball burned 30 times brighter than the sun. The flash quickly gave way to a shockwave that knocked people off their feet and shattered windows in thousands of apartments. No one was killed but more than 1,200 people were injured, many by flying glass. Some sustained retinal burns from watching the spectacle.

In 1908 the most powerful meteor blast in modern times shook the ground in Russia. The rock exploded over Tunguska, a sparsely populated region in Siberia, and flattened an estimated 80 million trees over an area of 770 sq miles.


Guardian News

Yellowstone Geysers Are Getting More Active

Yellowstone Geysers Are Getting More Active. Nobody's sure why

The geysers in Yellowstone National Park are as breathtakingly beautiful as they are mercurial. Old Faithful is famous in part because of its predictability, since most of these natural fonts are much more inscrutable.

Something odd is going on in Yellowstone National Park. Geysers that would once erupt every half century are now spouting steam every week.

And, late last year, one slumbering geyser — dubbed Ear Spring — vomited up 80 years worth of trash. The spring’s last big blow was in 1957. So, when it blew to a height of some 9m in September, National Parks officers spent days collecting old coins, beer cans, and even a 1930s baby dummy from its surrounds.

“An approximately 8-foot diameter area of surrounding ground is ‘breathing’ — rising and falling by about six inches every 10 minutes,” USGS researchers said.

While the eruption offered up an interesting time capsule, it’s also represents of what researchers are calling an unusual upturn in geyser activity.

The Steamboat geyser used to erupt erratically, sometimes after a duration as short as four days or as long as 50 years. Lately, it’s been sending spouts of steaming water 90m high into the air once every week.

The Yellowstone Volcano Observatory says it erupted 32 times last year.

What’s Going on?

However, USGS and park officials have stressed in recent months that there have been no signs of volcanic activity.

“Changes in Yellowstone’s hydrothermal features are common occurrences and do not reflect changes in activity of the Yellowstone volcano,” they said in a statement.

This is because the hydrothermal system — where water pools among the cracks in the rocks of the earth’s surface — is limited to mainly just the top 30m or so.

The magma that triggers volcanic activity resides several kilometres deeper.

“There has been no significant increase in seismicity nor broadscale variations in ground movement,” the USGS says.

And the geysers’ behaviour remains erratic.

“It’s a good lesson in how geysers actually work,” Michael Poland, the scientist-in-charge at Yellowstone Volcano Observatory, told National Geographic . “As soon as you start to recognise a pattern, it changes.”

Apocalypse? Nope.

With all this in mind, do we know what’s going on at Yellowstone? There’s been no change in the underlying heat source, and no major geological changes, Poland says.

However, the last few years have been exceptionally snowy, so a change in the supply of subsurface water may be a major factor. As it happens, the second-longest earthquake swarm in the park’s recorded history took place in 2017. Research tentatively suggests that the same heavy precipitation may have provided the faults involved with plenty of lubrication, allowing them to jut forward with reckless abandon.

In both cases, it’s difficult to make any definitive statements. There aren’t really any direct measurements of the subsurface water in the park, and such inferences are based on the records of surface water and precipitation. For now, Poland says, “we’re just speculating.”

What absolutely isn’t worth speculating about is the state of Yellowstone’s infamous volcanic system. Any uptick in any sort of activity at Yellowstone seems to spark fears about a catastrophic eruption of the park’s huge caldera, even though such worries are unfounded.

There has been no change to the underlying magma reservoir over the past few years, Poland emphasizes. Plus, the mischief of any of the park’s geysers—which operate at the very top of the crust—has no bearing whatsoever on that mostly solid magma cache many miles below the surface.

Further reading:

National Geographic

News.com.au

A Way to Make Invisible Gold Visible

Scientists Found a Way to Make Invisible Gold Visible

Scientists are using the new Geoscience Atom Probe Facility at Curtin University to study mineral deposits containing locked resources of gold in refractory ores.

Curtin WA School of Mines Research Associate in Applied Geology Dr Denis Fougerouse and fellow researchers have found metallic gold nanoparticles only a few nanometres in diameter within the mineral arsenopyrite – a common mineral found in Australian mines.

 Dr Fougerouse said the study was believed to be one of the first of its kind, and the discovery challenges the understanding of nanoparticle formation and allowed the team to establish the main controls on gold incorporation in sulphides.

“The application of atom probe microscopy in geosciences is relatively new. The technique is based on field-evaporation of atoms from tiny, needle-shaped specimens to provide three dimensional sub-nanometre scale information of the position and type of individual atoms in the specimen in the mineral,” Dr Fougerouse said.

“Typically, the amount of material analysed is really, really small – a single grain of salt is over a billion times larger than a typical analysis.”

Dr Fougerouse explained large resources of these nanoparticles are ‘locked’ in gold-bearing arsenopyrite, an iron arsenic sulphide, which can be found in mines across the world.

“Arsenopyrite is a very common mineral found in Australian and other mines, and although not every arsenopyrite contains gold, it is common to find gold locked inside this mineral,” he said.

“Our results show that gold can be hosted either as nanoparticles or as individual atoms in different parts of the crystal structure, and the different types of gold yield important information about the controls on gold deposition as the ore body forms.”

Dr Fougerouse explained this study demonstrated the capability of atom probe microscopy in geosciences.

“Our research shows the Geoscience Atom Probe has potential to characterise gold deposition processes at the atomic level. In turn this could help unlock hidden gold resources in known deposits, and will enhance gold recovery,” Dr Fougerouse said.

“Nanogeoscience is a new, but rapidly growing research field. Through this research and use of the Geoscience Atom Probe, we can show that tiny observations can yield big results that have potential economic importance.”


The above post is reprinted from materials provided by Curtin University.

Mysterious Stone Ball Discovered

Mysterious Massive Stone Ball Discovered by Bosnian

                              

A 10-foot-wide, stone ball recently discovered in a Bosnia forest is touching off a hot debate in academic circles: Was it created by Mother Nature … or a lost civilization?

An archaeologist is looking at a rock with great interest, a sphere unearthed in a forest, believed to be part of ancient civilization. Or is it just a very big rock?

A stone ball in Podubravlje village near Zavidovici, Bosnia and Herzegovina was seen earlier this month, in the ground, in a forest.

What can it tell us? Archaeologist Sam Osmanagich, who called his Bosnian stone ball the most massive in Europe, has some interesting answers.

"I've been researching prehistoric stone ball phenomenon for 15 years," he blogged last month. 

"By the mid of March 2016, it became obvious that the most massive stone ball in Europe has been discovered. Name of the location is village Podubravlje."

He said actually less than half of the ball is uncovered. "Preliminary results show the radius to be between 1.2 – 1.5 meters. Materials have not been analyzed yet. However, brown and red color of the ball point to very high content of the iron. So, the density has to be very high, close to the iron which is 7,8 kg/m3. If we take value of only 5 kg/c.c. we have all the elements for the preliminary calculation of the mass. Mass comes to be over 30 tons!"

Why does he view this discovery as significant? "First, it would be another proof that Southern Europe, Balkan and Bosnia in particular, were home for advanced civilizations from distant past and we have no written records about them. Secondly, they had high technology, different than ours. Finally, they knew the power of geometrical shapes, because the sphere is one of the most powerful shapes along with pyramidal and conical shapes. No wonder, that pyramids and tumulus phenomena can also be found in Bosnia."

News.com.au said Osmanagich had examined granite stone balls in southern Costa Rica, volcanic stone spheres in western Mexico and Easter Island, and then turned his attention to Bosnia.

If the huge stone in Bosnia is found to be hewn by human hands, it would be the largest man-made stone ball ever found - twice as heavy as the Costa Rican ones, said.

Do other experts see the rock formation as proof of an ancient civilization which thrived there? Voice of America reported that some scientists said the rock was likely a natural formation and not a human construct.

Experts were quoted in MailOnline as saying they believed the boulder was not man made.

A lecturer at the University of Manchester School of Earth, Atmospheric and Environmental Sciences told MailOnline that the spherical stone may be an example of concretion. This is when a compact mass of rock is formed by the precipitation of natural mineral cement within the spaces between sediment grains. The result is often spherical in shape, with the process forming the famed Koutu boulders in New Zealand.

Experts at the Geological Society, according to MailOnline, said the round shape of the rock could come from spheroidal weathering. This is a type of weathering affecting jointed bedrock. The result is formation of concentric or spherical layers of highly decayed rock.

The above story is based on materials provided by Phys.org

Secrets Of Diamond Formation

Unraveling Secrets of Diamond Formation

Understanding the global carbon cycle provides scientists with vital clues about the planet's habitability.

It's the reason why the Earth has a clement stable climate and a low carbon dioxide atmosphere compared to that of Venus, for instance, which is in a runaway greenhouse state with high surface temperatures and a thick carbon dioxide atmosphere.

One major difference between Earth and Venus is the existence of active plate tectonics on Earth, which make our environment unique within our solar system.

But the atmosphere, oceans, and Earth's crust are only part of the story. The mantle, which represents 75% of Earth's volume, potentially holds more carbon than all other reservoirs combined.

Carbon – one of the essential building blocks of organic life – is taken into Earth's interior by subduction, where it drastically lowers the melting point of the solid mantle, forming carbonated melts (carbon-rich molten rocks) in the shallow mantle, fuelling surface volcanoes. Carbonate minerals may also be transported much deeper into the Earth, reaching the lower mantle, but what happens next is uncertain.

Answering that question is beset with challenges – conditions deep within the Earth are extreme and samples from the mantle are rare. The solution is to recreate those conditions in the lab using sophisticated technology.

Now a team of experimental geoscientists from the University of Bristol have done just that. Their results, published open access in Earth and Planetary Science letters, uncover new clues about what happens to carbonate minerals when they are transported into the mantle via subduction of the oceanic crust (where one of Earth's tectonic plates slides below another).

Their findings have uncovered a barrier to subduction of carbonate beyond depths of around 1,000km, where it reacts with silica in the oceanic crust to form diamonds that are stored in the deep Earth over geological timescales.

Dr. James Drewitt from the School of Earth Sciences explains: "Do carbonate minerals remain stable through the Earth's lower mantle, and if not, what pressure/temperature changes does it take to spark reactions between the minerals and what do they look like? These are the questions we wanted to find the answers to – and the only way to get those answers was to reproduce the conditions of the Earth's interior."

Dr. Drewitt and his team subjected synthetic carbonate rocks to very high pressures and temperatures comparable to deep Earth conditions of up to 90 GPa (about 900,000 atmospheres) and 2000 degrees C using a laser-heated diamond anvil cell. They found that carbonate remains stable up to depths of 1,000-1,300km, almost halfway to the core.

Under these conditions carbonate then reacts with surrounding silica to form a mineral known as bridgmanite, which forms most of the Earth's mantle. The carbon released by this reaction is in the form of solid carbon dioxide. As the hot surrounding mantle eventually heats up the subducted slab, this solid carbon dioxide breaks down to form superdeep diamonds.

Dr. Drewitt adds: "Eventually the superdeep diamonds could be returned to the surface in upwelling mantle plumes, and this process could represent one of the sources of superdeep diamonds that we find at the surface and which provide the only direct evidence we have of the composition of the deep earth.

"This is exciting because the deepest humans have ever been able to drill is about 12 km, less than half the depth of Earth's crust. This pales in comparison to the massive scale of Earth's mantle, which extends to nearly 3,000 km depth."

The team used a diamond anvil cell to generate pressures equivalent to those found at these depths, loading samples under a microscope into a pressure chamber drilled out of a metal gasket which is then compressed between the gem quality, brilliant cut diamond anvils. The crystal structure of those samples was then analysed using X-ray diffraction at the UK synchrotron facility in Oxfordshire.

Dr. Drewitt now plans to apply these high pressure and high-temperature experiments along with advanced computer simulation techniques to other minerals and materials, adding: "As well as carbon, there is potentially several ocean's worth of water transported deep into the mantle, and when released this will induce melting of Earth's upper and lower mantle.

"However, we cannot adequately test or understand current models of the dynamic behaviour of this water rich molten rock because we do not know their composition or their physical properties. The experiments at extreme conditions and advanced computer simulations that we are currently working on will help to resolve these problems."



The above story is based on Materials provided by University of Bristol.