Phys.org December 12, 2022 Acoustic-gravity waves propagated by the eruption and tsunami caused global complex ionospheric disturbances. Researchers at the University of Washington studied the nature of the perturbations from Global Navigation Satellite System observables over the southwestern Pacific. After processing data from 818 ground stations, they detected supersonic acoustic waves, Lamb waves, and tsunamis, with filtered magnitudes between 1 and 7 Total Electron Content units. Phase arrivals appeared super positioned up to ∼1,000 km from HTHH and were distinct by ∼2,200 km. Within ∼2,200 km, signals had an initial low-frequency pulse that transitioned to higher frequencies. They found the […]
Tag Archives: Tsunami
Scientists provide explanation for exceptional Tonga tsunami
Phys.org June 13, 2022 The colossal eruption of the Hunga Tonga-Hunga Ha’apai volcano and ensuing tsunami is the first global volcano-triggered tsunami recorded by modern, worldwide dense instrumentation, thus providing a unique opportunity to investigate the role of air-water coupling processes in tsunami generation and propagation. An international team of researcher (Portugal, UK, USA – Columbia University, Spain) used sea-level, atmospheric and satellite data from across the globe, along with numerical and analytical models, to demonstrate that this tsunami was driven by a constantly moving source in which the acoustic-gravity waves radiating from the eruption excite the ocean and transfer […]
Hidden magnitude-8.2 earthquake source of mysterious 2021 global tsunami
Phys.org February 8, 2022 The 2021 August South Sandwich Island Mw 8.2 earthquake was a surprise, because it was initially reported as a magnitude 7.5 event at a deep depth (47 km) but generated a global-spreading tsunami that would only be expected for a larger and shallower event. By using seismic data researchers at Caltech revealed a hidden Mw 8.16 shallow slow event that happened between clusters of regular ruptures in the beginning and end. Although the slow event contributed 70% of the seismic moment, lasted three minutes, and ruptured a 200-km section of the plate interface, it is essentially […]
Tsunamis’ magnetic fields are detectable before sea level change
Phys.org December 21, 2021 The motion of conductive seawater by tsunamis can generate magnetic fields in the presence of the background geomagnetic main field. Previous studies found that, using the tsunami-generated seafloor magnetic field, it is possible to predict the propagation direction and wave height prior to the actual arrivals of tsunamis. In this study researchers in Japan correlate the tsunami magnetic field and the tsunami sea level change using observed data and three-dimensional simulations of the 2009 Samoa and 2010 Chile tsunamis. Their direct comparison of the tsunami observed magnetic field and tsunami sea level change illustrated that the […]