Abstract
Using the ionospheric total electron content (TEC) data from ground-based Global Navigation Satellite System (GNSS) receivers in Japan, we compared ionospheric responses to five explosive volcanic eruptions 2004–2015 of the Asama, Shin-Moe, Sakurajima, and Kuchinoerabu-jima volcanoes. The TEC records show N-shaped disturbances with a period ~ 80 s propagating outward with the acoustic wave speed in the F region of the ionosphere. The amplitudes of these TEC disturbances are a few percent of the background absolute vertical TEC. We propose to use such relative amplitudes as a new index for the intensity of volcanic explosions.Graphical
Highlights
The Earth’s ionosphere ranges from ~ 60 to > 800 km in altitude and is characterized by large number of free electrons
Ionospheric conditions are controlled by solar radiation and often disturbed by geomagnetic activities
In addition to such disturbances caused by space weather, the ionosphere is disturbed by events below (Blanc 1985), such as earthquakes (Heki 2021), tsunami (Occhipinti et al 2013), human-induced explosions (Kundu et al 2021), and volcanic eruptions
Summary
The Earth’s ionosphere ranges from ~ 60 to > 800 km in altitude and is characterized by large number of free electrons. The second type of disturbances occur 8–10 min after volcanic explosions by short pulses of acoustic waves propagating upward from the surface to the ionospheric F region (Fig. 1). They make short-term N-shaped impulsive TEC responses as Heki (2006) observed with the GPS-TEC method after the Vulcanian explosive eruption of the Asama volcano, Central Japan, on September 1, 2004. We explore the possibility to use the amplitude of ionospheric disturbance that occur ~ 10 min after a large explosion as the new index For this purpose, we compare ionospheric TEC responses to five recent explosive volcanic eruptions of four volcanoes in Japan 2004–2015 comparing the GNSS-TEC data from GEONET (GNSS Earth Observation Network), a continuous GNSS network in Japan. Additional file 1: Fig. S5 compares the synthesized STEC waveforms at various distances from the
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
