Phys.org April 20, 2022 Even with real-time geophysical monitoring, forecasting sudden eruptions is difficult, because their precursors are hard to recognize and can vary between volcanoes. An international team of researchers (New Zealand, Belgium) has described a general seismic precursor signal for gas-driven eruptions, identified through correlation analysis of 18 well-recorded eruptions in New Zealand, Alaska, and Kamchatka. The precursor manifested in the displacement seismic amplitude ratio between medium (4.5–8 Hz) and high (8–16 Hz) frequency tremor bands, exhibited a characteristic rise in the days prior to eruptions. They interpreted this as formation of a hydrothermal seal that enables rapid pressurization of […]
Tag Archives: volcano detection
Tonga Islands: A seismic algorithm reveals the magnitude of the January 2022 eruption
Phys.org April 20, 2022 By analyzing the seismic waves researchers in France were able to design an algorithm that can detect and locate a volcanic eruption in near real-time and, using equations that describe explosive eruptions, assess its size. Until now, such an assessment required field work and took several weeks or months, since it was necessary to estimate the volume of ash and lava produced. The authors show that the Hunga Tonga eruption ejected a volume of around 10 km3, making it the largest explosive eruption of the twenty-first century, equivalent in strength to that of the devastating eruption […]