Volcanoes are not restricted to the land, there are many undersea versions. One such undersea volcano known as Hunga Tonga-Hunga Ha’apai off the coast of Tonga. On 15th January 2022, it underwent an eruption which was one of the most powerful in recent memory. A recent paper shows that seismic waves were released 15 minutes before the eruption and before any visible disruption at the surface. The waves had been detected by a seismic station 750km away. This is the first time a precursor signal has been detected.  Undersea volcanoes are openings in the Earth’s crust beneath the ocean, where magma from the mantle escapes, triggering eruptions. They are surprisingly common, with most of Earth’s volcanic activity occurring underwater, particularly along mid-ocean ridges and subduction zones. They play a vital role in creating new seafloor through seafloor spreading, as magma cools and solidifies into basaltic crust. Some grow so tall that they rise above the ocean’s surface, forming volcanic islands such as Iceland and Hawaii. Their eruptions release significant amounts of gas, heat, and minerals into the surrounding water, shaping marine ecosystems. An erupting undersea volcano forms a new island off the coast of Nishinoshima, a small unihabited island in the southern Ogasawara chain of islands. The image was taken on November 21, 2013 by the Japanese Coast Guard. The Hunga Tonga-Hunga Ha’apai volcano is an undersea volcano located in the South Pacific. It became well known after its massive eruption in January 2022. The eruption was one of the most powerful volcanic events of the 21st century, triggering tsunamis that affected coastlines as far away as Japan and the Americas. The explosion released a plume of ash, gas, and water vapour, reaching over 50 kilometres into the atmosphere, making it the highest plume ever recorded. It impacted global weather patterns and temporarily increased water vapour in the stratosphere. The eruption of January 2022 formed a caldera on Hunga Tonga-Hunga Ha’apai. There were disturbances that were recorded by many surface stations and satellites in orbit. The data which had been captured revealed that the eruptions began just after 04:00 UTC on 15 January. There were a number of reports of seismic waves from around 15 minutes before the onset of eruption. In a paper published recently by lead author Takuro Horiuchi and a team from the University of Tokyo, they explore the wave detection and mechanics of the eruption.  Volcanic eruptions at Mt. Etna from orbiting NASA Terra Satellite. Acquired on January 11, 2011. NASA Earth Observatory Image of the Day on January 15, 2011. Credit: NASA Terra Satellite The team aim to confirm that the event actually occurred just before the 04:00 published timestamp. If they can confirm this, it will help understand the processes that led to the violent eruption. At the time of the eruption, no seismic stations had been working on Tonga but data had been recorded as far away as Fiji and Futuna, both of which around 750km away from the volcano.  The study concluded that the waves which had been detected were Rayleigh waves – a type of seismic waves which are a combination of compression (longitudinal) and shearing (vertical) movements. The waves started around 03:45 on the 15th January 15 minutes before the onset of the eruption. This is the first time significant seismic activity has been seen before the eruption event. It demonstrates that seismic stations hundreds of kilometres away can be positively used to detect signals as precursors to eruptions. Source : A Seismic Precursor 15 min Before the Giant Eruption of Hunga Tonga-Hunga Ha’apai Volcano on 15 January 2022 The post There Was a 15 Minute Warning Before Tonga Volcano Exploded appeared first on Universe Today.

Exploring the Moon poses significant risks, with its extreme environment and hazardous terrain presenting numerous challenges. In the event of a major accident, assistance might take days or even weeks to arrive. To address this, Australian researchers have created a distress alert system based upon the COSPAS-SARSAT technology used for Earth-based search and rescue operations. It relies on low-power emergency beacons that astronauts could activate with minimal setup and use a planned lunar satellite network for communication and rescue coordination. Fortunately I have never had to raise a distress call. I can imagine it though, somewhere remote, some sort of accident perhaps and need to summon assistance. Even on Earth, most mobile phone systems will be able to use a satellite signal to get a message out even if no cell signal. It’s not so easy on the Moon.  Even communication is delayed by just over a second but if someone needs to come and help, then you are really in trouble. That’s what the team from Australia identified and have addressed in their paper published in October 2024.  Aldrin on the Moon. Astronaut Buzz Aldrin walks on the surface of the moon near the leg of the lunar module Eagle during the Apollo 11 mission. Mission commander Neil Armstrong took this photograph with a 70mm lunar surface camera. While astronauts Armstrong and Aldrin explored the Sea of Tranquility region of the moon, astronaut Michael Collins remained with the command and service modules in lunar orbit. Image Credit: NASA As part of NASA’s Artemis program (which aims to create a sustained human presence on the Moon) astronauts will face significant dangers in isolated regions such as the lunar south pole. To address these challenges, researchers at the University of South Australia (UniSA) have been leading a project focused on developing an emergency response system. It’s designed to deliver critical safety warnings, enable incident reporting, and track the locations of astronauts that may be in trouble.  NASA’s Space Launch System rocket carrying the Orion spacecraft launches on the Artemis I flight test, Wednesday, Nov. 16, 2022, from Launch Complex 39B at NASA’s Kennedy Space Center in Florida. Credit: NASA/Joel Kowsky. The Artemis program is the focus of returning humans to the Moon. If successful it will mark the first crewed lunar missions since the days of the Apollo missions. With a focus on exploration and scientific discovery, Artemis aims to land astronauts, including the first woman and the first person of colour, on the Moon’s surface in 2025. Scientists from Adelaide and the United States are collaborating to develop a satellite constellation – like those launched by SpaceX but on a smaller scale – dedicated to improving communication and navigation on the Moon. The system will allow astronauts to transmit emergency alerts to a network of satellites which will then forward the data to Earth or nearby lunar stations. Founder of Safety from Space and adjunct researcher Dr Mark Rice explains that the system can provide continuous communication with astronauts for up to 10 hours! Even if they are in mountainous or heavily cratered terrain, the system will perform well. The group Safety from Space was formed in 2018 and has been awarded $100,000 from the Government to help with lunar search and rescue (LSAR) initiatives. The trial aims to provide astronauts with a lighter, more reliable radio beacon with a much longer battery life. If successful, the solution could enable significant Australian contributions to the Artemis program. It could even help to improve emergency communications here on Earth, especially in areas where mobile phone signals are not reliable.  Source : New lunar distress system could safeguard future astronauts The post How Could Astronauts Call for Help from the Moon? appeared first on Universe Today.

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