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Volcanoes

Mauna Loa volcano in Hawaii: The lava flows slowly towards the valley

by archyde December 1, 2022

Nighttime images impressively show the volcanic eruption on Hawaii and how the lava moves along Mauna Loa. The lava is currently shooting up about 25 meters from the crater, which is easy to see from a great distance, especially in the dark.

Mauna Loa is one of the largest active volcanoes on earth – some sources say it is THE largest active volcano in the world.

According to the seismic authority, the eruption is not currently threatening any residential areas – but the lava is moving towards a highway.

Mauna Loa’s volcanic eruption began on November 27, 2022.

dr USGS’ Kenhan told reporters on the ground that the lava was flowing very slowly down the valley. He assumes that the lava will only reach the next highway, the so-called Saddle Road, in two days. In fact, there are several streams, but they flow together.

According to the experts’ calculations, the movement of the largest stream has continued to slow down and was last at a speed of 0.02 miles per hour, or 24 meters per hour.

Many tourists and day trippers take the opportunity to take selfies with the volcano.

The volcanologists also say that the eruption is just beginning and will probably last several weeks.

December 1, 2022 0 comment

Technology

Volcanoes have turned “Twin Earth” into hell

by archyde November 24, 2022

Venus has been described as a “damn hell”, with a surface temperature of more than 464 degrees Celsius, hot enough to melt lead and spacecraft.

And a new study published by Russia Today, yesterday, showed that huge volcanic eruptions over a long period of time may be responsible for changing the planet to what it is today.

The study says that perhaps the massive volcanoes that covered 80 percent of the surface of Venus with lava were the decisive factor that transformed “Venus” from a wet and mild world into a stifling, sulfur and hellish planet as it is today.

However, there is growing evidence that Venus wasn’t always this way, and could one day have been a temperate world more or less similar to Earth, geologically speaking, than might have been expected.

In the latest paper, Michael Way of NASA’s Goddard Space Flight Center and his team argue that Venus’ volcanism could ultimately be what pushed it over the edge.

November 24, 2022 0 comment

Technology

Why Tonga’s eruption has been so violent and what could happen next

by archyde January 23, 2022

The kingdom of Tonga does not usually attract world attention, but the violent eruption of an underwater volcano January 15th has sent shock waves literally across half the world.

High-resolution Himawari satellite imagery of the #HungaTongaHungaHaapai volcanic eruption in Tonga 🌋
Our climate stations recorded a brief spike in air pressure as the atmospheric shock wave pulsed across New Zealand. pic.twitter.com/BfLzdq6i57
– NIWA Weather (@NiwaWeather) January 15, 2022

Normally, the volcano doesn’t look like much to the naked eye. It consists of two small uninhabited islands, Hunga-Ha’apai and Hunga-Tonga, which rise about 100 m above sea level 65 km north of Nuku’alofa, the capital of Tonga. But under the water lies a huge volcano about 1,800 m high and 20 km wide.

The huge underwater volcano next to the Hunga-Ha’apai and Hunga-Tonga islands.

The Hunga-Tonga-Hunga-Ha’apai volcano has erupted regularly in recent decades. In 2009 and 2014/15, hot jets of magma and steam exploded over the waves. However, these eruptions were small compared to the January 2022 phenomenon.

Our research on previous eruptions suggests that the most recent is one of the massive explosions that the volcano is capable of producing approximately every thousand years.

Why are the volcano eruptions so explosive, if the sea water should cool the magma?

If magma rises through water slowly, even at temperatures of about 1,200 ℃, a thin film of steam forms between the magma and water. This provides an insulating layer that allows the outer surface of the magma to cool.

But this process does not work when the magma comes out of the ground filled with volcanic gas. As material rapidly enters the water, the vapor layers rapidly break up, bringing hot magma into direct contact with cold water.

Volcanologists call this “fuel-coolant interaction” and it is similar to weapons-type chemical explosions. Extremely violent explosions rip apart the magma. A chain reaction is then started, with new magma fragments exposing new hot interior surfaces to the water, and the explosions repeat themselves, finally throwing out volcanic particles and causing explosions with supersonic speeds.

The two scales of the Hunga eruptions

The 2014/15 eruption created a volcanic cone, joining the two former Hunga islands to create a combined island about 5 km long. We visited it in 2016 and discovered that these historical eruptions were nothing more than opening act for the main phenomenon.

Mapping the seabed, we discovered a hidden “caldera” 150m below the waves.

A map of the seafloor shows the volcanic cones and the huge caldera. Author provided

The caldera is a crater-shaped depression about 5 km in diameter. Small eruptions (like the ones in 2009 and 2014/15) occur mostly at the caldera rim, but very large ones come from within the caldera itself. These large eruptions are so large that the top of the erupting magma sinks inward, deepening the caldera.

After looking at the chemistry of past eruptions, we think the small eruptions represent the magma system slowly recharging itself in preparation for a big event.

We found evidence of two huge past Hunga caldera eruptions in the deposits of the ancient islands. We compared them chemically with volcanic ash deposits on the largest inhabited island, Tongatapu, 65 km away, and then used radiocarbon dates to show that major caldera eruptions occur about every 1,000 years, the last of which in the year 1100.

With this knowledge, the January 15 eruption appears to be right on schedule for one of the big ones.

What can we expect to happen now?

We are still in the midst of this major eruptive sequence and many things remain unclear, in part because the island is currently obscured by ash clouds.

The two previous eruptions, on December 20, 2021 and January 13, 2022, were moderate in size. They produced clouds up to 17km high and added new land to the combined 2014/15 island.

The latest eruption has increased the scale in terms of violence. The ash plume is already about 20 km high. The most remarkable thing is that it spread almost concentrically to a distance of about 130 km from the volcano, creating a plume with a diameter of 260 km, before it was distorted by the wind.

This supposes an enormous explosive power, which cannot be explained solely by the magma-water interaction. Instead, it shows that large amounts of fresh, gas-laden magma have exited the caldera.

The eruption also produced a tsunami throughout Tonga and in neighboring Fiji and Samoa. The shock waves traveled many thousands of kilometres, were seen from space and were recorded in New Zealand some 2,000 km away. Shortly after the start of the eruption, the sky was obscured at Tongatapu, and ash began to fall.

All these signs suggest that Hunga’s great caldera has awakened. Tsunamis are generated by coupled atmospheric and oceanic shock waves during an explosion, but are also easily caused by submarine calving and caldera collapses.

It is not yet clear if this is the climax of the eruption. It represents an important release of magma pressure that can calm the system.

However, the geological deposits from the volcano’s previous eruptions contain a warning. These complex sequences show that each of the major caldera eruption episodes every 1000 years involved many separate blast events.

Tonga reports “major damage” after volcano eruption and tsunami

by archyde January 18, 2022

Reconnaissance flights launched as smoke from the volcano cleared reveal the magnitude of the disaster

Relief agencies reported on Tuesday “Great damage” in Tonga after the massive eruption of an underwater volcano followed by a tsunami in this Pacific archipelago, where one death from the disaster was confirmed. The first indications of the magnitude of the crisis in the island country began to be known through irregular satellite phone calls and satellite images, three days after the eruption.

The body of a British woman swept away by the tsunami has been found, her family said, and at least one other person has been reported missing. The number of victims of the tragedy is unknown. Meanwhile, two Mexican biologists were trapped in Tonga although they are out of danger, while the government and their families are trying to get them out, the Mexican Ministry of Foreign Affairs said. In turn, Peru isolated three beaches in the province of Callao after an oil spill attributed to the abnormal waves recorded after the eruption volcanic in Tonga, reported the Environment Ministry. On Saturday, two women from that country died swept away by the waves.

The UN Office for the Coordination of Humanitarian Affairs (OCHA) revealed that surveillance flights confirmed “substantial property damage” on Mango and Fonoi islands. “An active distress signal was detected in Mango“, indicated OCHA in an urgent report. The island has about 30 inhabitants, according to the Tonga census. The agency also reported “great damage” on the western beaches of the main island Tongatapu, “with several hotels and/or houses destroyed and / or severely damaged”.

The capital Nuku’alofa was covered in two centimeters of volcanic ash and dust, while power was restored to parts of the city. Internal telephone systems were restored but international communication continued to be interrupted. The capital’s boardwalk was “seriously damaged by stones and debris carried inland by the tsunami,” OCHA said.

affected structures

Images released by the UN Satellite Center showed the impact of the eruption and tsunami on the small island of Nomuka, one of the closest to the Hunga-Tonga-Hunga-Ha’apai volcano. The center indicated that of 104 structures analyzed in the area that was not covered by clouds, 41 were identified as damaged and almost all covered with ash. Australia and New Zealand, which have sent Orion reconnaissance planes over the island, have prepared aid shipments for Tonga.

Australia noted that the ash from the airport had to be removed before landing a C-130 military plane with the help. OCHA was expecting this to be done by Monday, although the current situation is unknown. Water is one of the priorities, New Zealand Defense Minister Andrew Bridgman said for the risk that water sources have been poisoned by volcanic emanations.

Major relief agencies, which often come with emergency humanitarian aid, have said they are at a standstill unable to contact their local staff. “For the few updates we have, the magnitude of the devastation could be immenseespecially for the outlying islands,” said Katie Greenwood of the International Federation of the Red Cross regional branch. But even when relief efforts can start, they could be complicated by Covid-19 entry restrictions. Tonga recently reported its only case of coronavirus.

Saturday’s eruption was one of the largest in decades, sending ash, gas and acid rain spreading across the Pacific. The eruption was recorded around the world and heard as far away as Alaska, triggering a tsunami that inundated Pacific coastlines from Japan to the United States.

Communications cut

Tonga may spend weeks incommunicado until they fix the underwater cable connection, the company responsible for the link reported Tuesday. The scarce communication with this nation, made up of 169 islands and 105,000 inhabitants in the South Pacific, makes emergency tasks difficult and prevents knowing the current situation of the country after the relentless shaking of the waves. Tongan authorities have not yet been able to communicate with many of the inhabited islands, some of which rise only a few meters above sea level.

The cable linking communications to and from Tonga, linked from neighboring Fiji, has broken some 37 kilometers off the Tongan coast, confirmed Dean Veverka, chief technical officer of the Southern Cross Cable company. “These days, submarine cables carry about 99% of all communications between countries … Tonga will spend quite some time with limited communications,” the expert told Radio New Zealand.

A new eruption of Etna paralyzes flights in Sicily

by archyde December 14, 2021

A new eruption of the Etna volcano, located on the Italian island of Sicily, has forced the closure of airspace throughout the area and the suspension of air operations at Catania airport.

La Palma volcano: a 4.9 earthquake generated a new lava explosion | It is the largest since the beginning of the seismic swarm

by archyde October 23, 2021

The Spanish Atlantic island of La Palma, where the Cumbre Vieja volcano has been erupting since September 19, registered an earthquake of 4.9 magnitude 38 kilometers deep this Saturday, felt by the population.

The tremor, detected by the National Geographic Institute (IGN), is the largest since the seismic swarm that preceded the eruption began and during its duration.

Since a 4.3 earthquake was recorded early this Saturday, the IGN has located 30, of which a dozen exceeded magnitude 3.

https://twitter.com/CSIC/status/1451842704837685250

The main cone of the volcano has partially collapsed -according to the Instituto Volcanológico de Canarias, the Atlantic archipelago where La Palma is located-, and an IGN seismograph reported an emission of runoffs further west of the secondary cone, than in the last hours suffered several lava overflows.

“Back on La Palma to support the island. On Tuesday we will modify #CMin the Contingency Fund to accelerate the arrival of the approved aid and we will solve the demands of the self-employed. We are with the palm trees now and we will continue to be when the crisis ends, “said the president of Spain, Pedro Sánchez, through his Twitter account.

https://twitter.com/sanchezcastejon/status/1451883999564075008

The spills have widened the wash that worries the most at the moment, the one that has been stopped in the neighborhood of the town of La Laguna, with risk to buildings and crops.

Until now, the volcano has devastated about 900 hectares and has destroyed some 2,200 buildings, many of them homes, according to data from the Copernicus satellite system. In addition, some 7 thousand people had to be evicted since the beginning of the emergency

October 23, 2021 0 comment

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Volcanoes

The two scales of the Hunga eruptions

What can we expect to happen now?

Reconnaissance flights launched as smoke from the volcano cleared reveal the magnitude of the disaster

affected structures

Communications cut