Month: July 2018

Plate Tectonics Not Needed To Sustain Life

There may be more habitable planets in the universe than we previously thought, according to Penn State geoscientists, who suggest that plate tectonics — long assumed to be a requirement for suitable conditions for life — are in fact not necessary.

When searching for habitable planets or life on other planets, scientists look for biosignatures of atmospheric carbon dioxide. On Earth, atmospheric carbon dioxide increases surface heat through the greenhouse effect. Carbon also cycles to the subsurface and back to the atmosphere through natural processes.

“Volcanism releases gases into the atmosphere, and then through weathering, carbon dioxide is pulled from the atmosphere and sequestered into surface rocks and sediment,” said Bradford Foley, assistant professor of geosciences. “Balancing those two processes keeps carbon dioxide at a certain level in the atmosphere, which is really important for whether the climate stays temperate and suitable for life.”

Most of Earth’s volcanoes are found at the border of tectonic plates, which is one reason scientists believed they were necessary for life. Subduction, in which one plate is pushed deeper into the subsurface by a colliding plate, can also aid in carbon cycling by pushing carbon into the mantle.

Planets without tectonic plates are known as stagnant lid planets. On these planets, the crust is one giant, spherical plate floating on mantle, rather than separate pieces. These are thought to be more widespread than planets with plate tectonics. In fact, Earth is the only planet with confirmed tectonic plates.

Foley and Andrew Smye, assistant professor of geosciences, created a computer model of the lifecycle of a planet. They looked at how much heat its climate could retain based on its initial heat budget, or the amount of heat and heat-producing elements present when a planet forms. Some elements produce heat when they decay. On Earth, decaying uranium produces thorium and heat, and decaying thorium produces potassium and heat.

After running hundreds of simulations to vary a planet’s size and chemical composition, the researchers found that stagnant lid planets can sustain conditions for liquid water for billions of years. At the highest extreme, they could sustain life for up to 4 billion years, roughly Earth’s life span to date.

“You still have volcanism on stagnant lid planets, but it’s much shorter lived than on planets with plate tectonics because there isn’t as much cycling,” said Smye. “Volcanoes result in a succession of lava flows, which are buried like layers of a cake over time. Rocks and sediment heat up more the deeper they are buried.”

The researchers found that at high enough heat and pressure, carbon dioxide gas can escape from rocks and make its way to the surface, a process known as degassing. On Earth, Smye said, the same process occurs with water in subduction fault zones.

This degassing process increases based on what types and quantities of heat-producing elements are present in a planet up to a certain point, said Foley.

“There’s a sweet spot range where a planet is releasing enough carbon dioxide to keep the planet from freezing over, but not so much that the weathering can’t pull carbon dioxide out of the atmosphere and keep the climate temperate,” he said.

According to the researchers’ model, the presence and amount of heat-producing elements were far better indicators for a planet’s potential to sustain life.

“One interesting take-home point of this study is that the initial composition or size of a planet is important in setting the trajectory for habitability,” said Smye. “The future fate of a planet is set from the outset of its birth.”

5.3-Magnitude Earthquake Hits Off Oregon Coast, No Tsunami Warning

A 5.3-magnitude earthquake struck off the coast of Oregon on Sunday morning, followed by a 4.4-magnitude quake in the same area about 40 minutes later, according to the U.S. Geological Survey.

The National Weather Service’s Tsunami Alerts Twitter page said that a “tsunami [is] not expected” after the 5.3 quake on Sunday.

The 5.3-magnitude quake struck at a depth of around 6 miles. It was located about 232 miles west from Coos Bay and 227 miles west from Charleston. Both are located in southern Oregon, said the agency.

On Tuesday morning, the USGS said that 11 quakes ranging from 2.8 to 5.6 magnitudes were reported off the Oregon and California coastline. They were clustered some 125 miles west of Crescent City, California, according to OregonLive.

Don Blakeman, who works as a geophysicist at the National Earthquake Information Center, told OregonLive that the magnitudes of the tremors haven’t yet been serious. Quakes of this caliber occur fairly often in the Pacific Ocean near the West Coast of the United States, he said.

He said that officials aren’t worried about a tsunami unless a magnitude-7 earthquake is reported.

The earthquakes took place along Juan de Fuca tectonic plate. Blakeman did note that the plate will be the likely source of a large earthquake in the Seattle and Portland area in the future, but nobody knows exactly when.

Meanwhile, Oregon, California, and the rest of the U.S. West Coast are located on the seismically active “Ring of Fire” located within the basin of the Pacific Ocean. It’s lined with around 75 percent of the world’s active volcanoes. The USGS says that about 90 percent of the world’s earthquakes take place along the ring.

Ibu Volcano (Halmahera, Indonesia): Explosive Activity And New Lava Flow

Ibu volcano, located along the NW coast of Halmahera Island, is a stratovolcano with a truncated summit and a number of large nested summit craters. The inner crater, 1 km wide and 400 m deep, contained several small crater lakes through much of historical time. The outer crater, 1.2 km wide, is breached on the north side, creating a steep-walled valley.

The volcano is very active at the moment, our expedition organizer Andi reported from the ongoing volcano tour to Ibu and Dukono volcanoes.

“Mt Ibu … (has) many explosions and a new lava flow has been active on the western flank.”

Indonesia Earthquake: Quake Hits Tourist Island Of Lombok

A powerful earthquake has struck an island in Indonesia early on Sunday morning.

The 6.4 magnitude quake hit the central island of Lombok just before 07:00 local time (00:00 UK time).

Indonesia is a country in south-east Asia, while the island of Lombok is somewhere where lots of people go on holiday.

Officials say at least 14 people have been killed and more than 160 people are injured.

Many buildings on the island are made from wood and bamboo.

Thousands of homes have also been damaged by the original earthquake and 11 aftershocks.

Sutopo Purwo Nugroho, a spokesman for the country’s disaster agency, said most people were injured when they were hit by debris and falling blocks of concrete.

He said: “The main focus now is evacuation and rescue. Some of the injured are still being treated at clinics.”

The US Geological Survey said the epicentre of the earthquake was 50km (31 miles) north-east of the city of Mataram, in northern Lombok.

It was followed by more than 60 smaller earthquakes, with the largest recorded at a magnitude of 5.7.

Mount Rinjani National Park, a popular destination for trekkers, has been closed due to landslides.

In some areas landslides have cut off roads, and the water supply and electricity to houses.

Indonesia often experiences earthquakes because it lies on an area called the Ring of Fire – where earthquakes and volcanic eruptions are frequent.

More than half of the world’s active volcanoes above sea level are part of the ring.

In 2016 a magnitude 6.5 quake struck off the north-east coast of Sumatra island, killing dozens of people and more than 40,000 having to leave their homes.

Volcano Watch: Geochemical Detective Work Helps Answer Questions About Kilauea’s Ongoing Eruption

“What’s happening inside the volcano?”

That’s just one of many questions asked about Kilauea’s ongoing lower East Rift Zone eruption. Looking at the geochemistry of erupted lava can help us answer these questions.

Magma supplying Kilauea’s eruption is composed of melt (molten rock), mineral crystals and dissolved gases or gas bubbles (exsolved gases). Elements that make up magma can stay in the melt or can build crystals depending on the magma temperature, pressure and abundance of other elements.

Experimental work found the elements magnesium and calcium move between the melt and specific mineral crystals depending on temperature. So, the amount of magnesium and calcium in lava reflects the temperature of the magma.

Some elements do not fit into any mineral crystals that grow in Hawaiian magma. These elements increase in concentration as magma cools and more crystals form. So, the abundances of these “incompatible” elements reveal if magma has been stored before erupting. If stored long enough, the magma’s composition is changed as crystals grow and the amounts of incompatible elements increase.

When the first lower East Rift Zone lava sample was collected May 3, the University of Hawaii at Hilo geochemistry lab swung into action, working with the USGS Hawaiian Volcano Observatory to determine, within hours, that the erupted lava was from stored magma. The LERZ lava was much cooler (about 1,090 degrees C or 2,000 degrees F) and more “evolved” than any Pu‘u ‘O‘o lava (typically 1,140 degrees C or 2,080 degrees F) erupted during the past 35-plus years. While this finding was not a surprise, it was the first time it was documented during an eruption.

But there was one surprise: Fissure 17 — the only vent not in line with the others — erupted the coolest and most chemically evolved lava ever found on Kilauea. Its temperatures were as low as 1,030 degrees C (1,890 degrees F).

Previous lower rift zone eruptions on Kilauea have shown a similar pattern — evolved magma erupted first followed later by hotter, “fresher” magma. The early LERZ lava erupted in Leilani Estates is similar in composition to the early 1955 lava, which erupted in the same area and seems to be the most likely candidate for the parental source.

Finding evolved magma stored in the lower regions of Kilauea, the site of many past eruptions and intrusions, is to be expected. During past events, not all of the magma reached the surface once the driving pressure was gone. That stored magma then evolved with time.

Because Kilauea is so massive, it can take decades before magma comes back to a given area. During that time, stored magma cools, grows crystals and slowly changes in composition. When a new intrusion forces its way through the volcano and up to the surface, it might encounter one or more of these stored magma bodies. The intrusion magma can push out and/or mix with any stored magma that is still liquid.

As the LERZ eruption continued, samples collected May 11 showed that the lava composition shifted to slightly hotter (1,105 degrees C or 2,020 degrees F) and less evolved magma. Soon afterward, eruptions from fissure 20 produced ‘a‘a flows that rushed to the ocean.

During the next 12 days, the lava chemistry became progressively hotter and less evolved until it leveled out at temperatures of 1,130–1,140 degrees C (2,070–2,085 degrees F). The arrival of this hotter lava preceded the high-volume, sustained eruption of fissure 8, giving scientists a heads-up that something might change.

This new lava includes abundant and visible olivine crystals, some of which resemble the type of olivine crystallizing in summit magma before the LERZ eruption sequence began. The lava composition we see now doesn’t exactly match recent Pu‘u ‘O‘o or summit lavas, but it is similar.

This correlates well with geophysical observations that the volume of the summit collapse is similar in magnitude to the volume of LERZ erupted lava.

Magma travels up to 45 km (28 mi) through Kilauea’s East Rift Zone, cooling and potentially mixing with stored deep-rift magma to create lava of slightly different compositions. Our ongoing geochemical detective work should help us get a better handle on what’s happening inside the volcano.

Volcano activity updates

On Kilauea Volcano’s lower East Rift Zone, lava continued to erupt primarily from fissure 8, feeding a channelized flow northeastward from the vent. The channel then extends west of Kapoho Crater and on to the main ocean entry near Ahalanui. As of July 27, the flow was less than 0.1 mi from the Pohoiki boat ramp at Isaac Hale Beach Park. Sulfur dioxide emissions from the active fissure remain high. Residents in the lower Puna District should stay informed and heed Hawaii County Civil Defense closures, warnings and messages (http://www.hawaiicounty.gov/active-alerts).

At Kilauea’s summit, collapse events continued to occur during the past week, releasing energy equivalent to earthquakes of about magnitude-5.3. Inward slumping of the rim and walls of Halema‘uma‘u continues in response to ongoing subsidence at the summit, resulting in frequent felt earthquakes. Three or more felt reports were submitted for 53 of the earthquakes that occurred in Hawaii during the past week.

At Mauna Loa, HVO seismic and deformation monitoring networks indicate the volcano is no longer at an elevated level of activity. Accordingly, HVO dropped the Mauna Loa alert level to Normal and the aviation color code to Green on June 21. HVO continues to monitor the volcano closely and will report any significant changes.

Weird Volcanoes Are Erupting Across the Solar System

NASA’s Juno spacecraft recently spotted a possible new volcano at the south pole of Jupiter’s most lava-licious moon, Io. But this volcanically active moon is not alone in the solar system, where sizzling-hot rocks explode and ooze onto the surface of several worlds. So how do Earthly volcanoes differ from those erupting across the rest of the solar system?

Let’s start with Io. The moon is famous for its hundreds of volcanoes, including fountains that sometimes spurt lava dozens of miles above the surface, according to NASA. This Jupiter moon is constantly re-forming its surface through volcanic eruptions, even to this day. Io’s volcanism results from strong gravitational encounters between Jupiter and two of its large moons, Europa and Ganymede, which shake up Io’s insides.

Rosaly Lopes, a senior research scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, managed observations of Io between 1996 and 2001, during the Galileo spacecraft mission to Jupiter.

“Io has lots of caldera-like features, but they are on the surface,” Lopes told Live Science. “There are lots of lava flows and lots of lakes. Lava lakes are pretty rare on Earth. We have half a dozen of them. We think they have occurred in the past on Venus and Mars. But on Io, we actually see lava lakes at the present time.” Hawaii’s Kilauea volcano is one such spot on Earth dotted with lava lakes. [Photos: Fiery Lava from Kilauea Volcano Erupts on Hawaii’s Big Island]

Juno scientists asked for Lopes’ help in identifying Io’s newly found hotspot. She said the new observations of Io are welcome, because Galileo was in an equatorial orbit and could rarely see the poles; by contrast, Juno is in a polar orbit and has a much better view. There are some hints that Io might have larger and less-frequent eruptions at the poles, she said, but scientists need more observations to be sure.

Venus and Mars volcanoes are all right tonight
Venus also appears to have active lava flows on its surface, where temperatures reach more than 800 degrees Fahrenheit (425 degrees Celsius). The few Soviet Venera spacecraft that landed there in the 1970s and 1980s lasted only a short while. Lopes said it’s unclear if Venus has active volcanoes currently, although multiple observations from Europe’s past Venus Express mission suggested it might. One example is Idunn Mons, which is a hotspot that may have erupted relatively recently.

Venus has dome volcanoes, or volcanoes with lots of peaks, although these volcanoes might be inactive. This kind of volcano is also common on Earth. A dome volcano is formed from eruptions of viscous (sticky) lava, with only a small percentage of gas that oozes out.

“Volcanologists call it two-face lava, because it hides itself and oozes out,” Lopes said. Mount St. Helens, in Washington state, is one such example, with several of these lava domes dotting its crater. Venus is also populated with other types of volcanoes and volcanic features — pancake domes (which look like pancakes), arachnoids (eroded calderas that look like spiders), lava flows and volcanic plains.

Venus and Mars also have shield volcanoes, a type of volcano made up almost entirely of fluid lava flows. (Shield volcanoes are common on Earth, in Hawaii in particular, Lopes said.) Mars possesses the highest volcano in the solar system — Olympus Mons — and several other monster volcanoes, perhaps because its gravity is lighter than Earth’s and the volcanoes can grow taller.

On Mars, the volcanoes appear to be dormant, as there are no visible recent lava flows on the surface. There’s extensive evidence of past volcanism, though. There are flood plains of basalts, as well as other types of volcanoes that “were formed by more explosive volcanism, because they are highly eroded on the flanks,” Lopes said.

Other worlds in our solar system also had lava volcanism in the ancient past, including Earth’s moon, Mercury and the dwarf planet Ceres, Lopes said. And then there are worlds with possible cryovolcanism — or icy volcanoes — in which the erupting material is water, or water mixed with nitrogen or methane.

There is evidence of active plumes at Jupiter’s moon Europa and Saturn’s moon Enceladus. Saturn’s moon Titan may also have past cryovolcanic features on its surface, Lopes’ research has found. Other worlds with possible cryovolcanism include Triton (Neptune’s largest moon), Pluto, and Charon (Pluto’s largest moon).

Typhoon Jongdari: Japan Storm Cuts Power To Thousands

A powerful storm has hit central and western Japan, injuring at least 21 people and cutting power to tens of thousands of homes.

Typhoon Jongdari (or “skylark” in Korean) brought torrential rain and winds of up to 180km/h (110mph).

It made landfall on the country’s main island, Honshu, at 01:00 (16:00 GMT Saturday) on Sunday.

Weather officials have since downgraded it to a tropical storm, but warn that heavy rain could trigger landslides.

Japan’s public broadcaster NHK reports that 150,000 homes are without power.

As of midday local time, the storm was moving westwards and tens of thousands had been urged to leave their homes.

On Saturday, evacuation orders were issued to 36,400 people in the western city of Shobara, and 6,300 in the city of Kure.

“We are afraid that people may not be able to evacuate due to strong wind or floods blocking evacuation routes,” said Hiroshima’s governor, Hidehiko Yuzaki.

“I would like people to evacuate in advance so that they can save their lives.”

Images have shown huge waves crashing on to rocks off the coast south-west of Tokyo, and ferry services have been suspended.

Late on Saturday, the rough seas smashed through the window of a hotel restaurant in the tourist town of Atami, injuring five people.

“We didn’t expect this could happen… Waves gushed into the restaurant as the window glass broke but we are grateful that customers followed evacuation instructions,” a hotel employee told AFP.

Hundreds of flights were also cancelled over the weekend as the storm neared the coast.

Weather-ravaged

Japan is still reeling from one of its worst flooding disasters in decades earlier this month, which saw more than eight million people ordered to leave their homes. More than 4,000 survivors are still living in temporary shelters.

The floods were swiftly followed by an unprecedented heatwave which was declared a natural disaster.

At least 80 people have been killed by the temperature, and more than 22,000 hospitalised with heat stroke.

The country is now in the grip of typhoon season, which sees tropical storms barrel across the Pacific throughout the summer months.