HAMNET Report 23rd January 2022


The undersea volcanic eruption about 40 miles away from the main Island of Tonga last Saturday turns out to have been a much bigger event than one might have expected. The explosion caused by the shifting of many cubic kilometers of tectonic material against the slopes of the known undersea volcano threw a column of ash steam and magma about 20 Km into the air, and created a tsunami wave that totally washed all the structures on Mango Island away, considerably damaged the main island, and probably many of the tiny islands comprising the 177 pieces of the nation of Tonga. The tsunami was measured as far afield as Peru, Japan, Morocco, the coast of Mediterranean France, and Malta.

The sound of the blast was heard 2300 Km away, and British radio amateurs, who had set up a little seismic recording station in Leicestershire some time before, picked up the seismic jolt or pressure wave, 16000 km away, about 10 hours later. The shock wave was said to have travelled at roughly 1150 Km/h to arrive in England when it did.

All communications with all the little islands were lost, and the only undersea fibre-optic cable to the islands was severed in at least one place, and may take several weeks to restore, so the death toll on the little atolls and islands has not been established. Most homes along the coast were swept away completely by the tsunami, and residents have lost all their possessions.

The first contactless aid flights arrived in Tonga on Thursday, as the almost coronavirus-free Pacific island nation took precautions to keep the virus out of its borders in the wake of the devastating volcanic eruption and tsunami.

Flights from Australia and New Zealand carrying humanitarian aid and disaster relief landed at Fua’amotu International Airport in Tonga’s capital, Nuku’alofa, after the runway was cleared of volcanic ash and debris following Saturday’s violent eruption of the volcano called  Hunga-Tonga-Hunga-Ha’apai.

Tonga has registered only one COVID-19 case to date, and any assistance from Australia or New Zealand is highly likely to introduce the Omicron virus, which will complicate matters in a country with no innate immunity to the virus. However, two New Zealand Naval vessels were due to arrive at Tonga with disaster relief supplies on Friday the 21st. The delivery of the aid will be contactless, so they will attempt to prevent further cases from happening. There are about 100000 people living on the Tonga islands.

I’m sure you have seen the amazing satellite pictures taken at exactly the right time, showing the shockwave under the sea, before the mix of magma, steam and ash reached the surface and exploded into the air.

Meanwhile, closer to home, GDACS reports that, since the 17th January, heavy rainfall and thunderstorms have been affecting Analamanga Region of Madagascar, particularly the capital Antananarivo, causing floods, triggering landslides and resulting in casualties and damage.

According to media reports, ten people have died, two others have been injured and approximately 500 have been displaced. In addition, widespread damage has been reported in the capital and surrounding areas, including collapsed houses and bridges. The city of Antananarivo has been placed on red alert against “imminent danger” by the city’s flood monitoring system. The Urban Commune of Antananarivo (CUA) has activated its contingency plan and has evacuated 3,000 people, helped by the national disaster management authorities (BNGRC).

Moderate rain with thunderstorms was forecast over most parts of Madagascar, particularly the central and whole eastern part of the country for Wednesday and Thursday of this week.

Kwa-Zulu Natal has also had its fair share of damage with Ladysmith totally inundated by floods since the beginning of this week. GDACS reports that heavy rainfall has been reported across central and eastern South Africa, causing floods and overflowing rivers, and resulting in casualties.

According to media, at least one person has been confirmed dead and dozens of people have been evacuated and relocated to evacuation centres in Ladysmith. Floodwaters have caused damage to houses and infrastructure across KwaZulu-Natal.

Evacuation operations have started for a number of people as water has been released from the Bloemhof and Vaal Dam, after the water levels of the Vaal River increased. As of 20th January, both the Bloemhof Dam and the Vaal Dam were at 111% capacity, as reported by the Water and Sanitation Department of South Africa.

And, at the Western edge of the country, heatwaves have been experienced over this weekend, with the Western Cape due to register the highest temperatures in the world yesterday and today. This forecast and weather warning was issued on Friday.

Don’t let anyone fool you into thinking that climate change is not real!

Now, a quick summary of the status of the James Webb Space Telescope, as of the beginning of the weekend. It was 4 weeks yesterday since the launch on Christmas day, and the telescope has been drifting ever closer to its stopping point at the L2 Lagrange point. After speeding away from the Earth after launch, it has slowed down considerably, simply braked by the Sun and Earth’s gravity, and is now drifting at 0.2 km/second, roughly 96% of the way to its destination. It has only 60000 km still to travel and will then go into a circular orbit, perpendicular to its line of sight with the Earth and Sun, so that its solar panels are not continuously blocked by a self-induced eclipse of the Sun by the Earth. Its heat shield, a five layered structure the size of a tennis court is keeping the telescope side at a comfortable -207 degrees Celsius, though the plan is to cool it down to within about 7 degrees of absolute zero by means of a Helium freezer unit.

Its hot side, facing the Earth and the Sun is measuring a maximum temperature of up to 60 degrees Celsius, so it shows how efficient the heat shield truly is. The Helium refrigeration hasn’t been switched on yet.

Insertion into its orbit at the L2 Lagrange point will occur on day 30 of its journey, in other words, tomorrow the 24th January.

All of the single point failure stages that should have been executed so far have been, flawlessly, and so far, the mission is a success. In that no extra fuel was required for any course corrections after launch, it is estimated that the JWST will be able to deliver science and data for at least 20 years, a truly remarkable endeavour.

This is Dave Reece ZS1DFR reporting for HAMNET in South Africa.