Hi Everybody: On Spaceweather.com there is a story about Rob Stammes of the Polarlightcenter, a magnetic observatory in Norway. He recorded a sine wave with a period of 15s that lasted for hours on his magnetometers on November 18 between 1800 to 2000 UTC. After I read this story, I was thinking about this oscillation. Would it show up in the RF-Seismograph? So I went back into my data and recreated the day Rob saw the incident. After reviewing the graph it was easily visible on 80m (red). Also interesting is the fact that the 20m (magenta) band started doing the same oscillation, even after the main wave stopped. Even though Rob used a magnetometer for his measurement the effects of the "rare wave" on background noise in the HF bands is quite strong! Also interesting is the effect on a global scale, since the two recording stations were basically on opposite sites of the world. How these waves effect propagation is not very well understood yet! For more information on how these "rare waves" are created in the magnetosphere check this link: http://roma2.rm.ingv.it/en/themes/22/magnetic_pulsations Watch it live here: http://users.skynet.be/myspace/mdsr/ All the best and 73; Alex - VE7DXW
There was a similar seismic wave recorded one week earlier. The source was just off Mayotte between Madagascar and Africa. They may not be connected but the frequency and purity of the wave is similar. More info on National Geographic: https://www.nationalgeographic.com/...ake-waves-rippled-around-world-earth-geology/ Regards, Chris, G4HYG
An earthquake with magnitude 7.0 occurred 13km N of Anchorage, Alaska at 17:29:28.91 UTC on Nov 30, 2018. Currently there is no Tsunami warning! We hope everybody is save; Alex - VE7DXW