Ionospheric disturbances before and after the January 14, 2018 eartquake in Peru

Abstract

An earthquake of Mw 7.1 occurred on January 14, 2018 in the southern coast of Peru. In this study, public available Global Ionospheric Maps (GIMs) provided by the Center for Orbit Determination in Europe (CODE) were used to look for ionospheric disturbances pre-and postearthquake. Twelve days before the seismic event, a positive anomaly was detected at low latitudes in the northern hemisphere in differential vertical total electron content maps. Moreover, given the low-latitude nature of this incident, changes in the shape of the Equatorial Ionization Anomaly (EIA) were analyzed as well. A significant amplification of the northern crest in the EIA of 33.3 % was also observed 12 days before the earthquake. Because the geomagnetic and solar conditions for January 2, 2018 were very quiet and also knowing that natural ground radioactivity produced by the earthquake's preparation can increase the total electron density in the EIA, it is considered that this ionospheric disturbance is product of the earthquake's preparation. Additionally, the detection of a negative ionospheric anomaly 2 days after the incident is reported. An association to the earthquake of this negative disturbance is hinted at, due to the also the rather quiet geomagnetic and solar conditions after the seismic occurrence.

Wide-bandwidth Observations of PSR J0941–39 and PSR J1107–5907

“…We used RMFIT to determine the RM (RM obs ) of PSR J0941-39 and PSR J1107-5907. The ionospheric RM contribution (RM ion ) for each pulsar was measured using IONFR (Sotomayor-Beltran et al 2013a, 2013b. The RM contribution from the interstellar medium is RM ISM = RM obs − RM ion .…”

Deep Synoptic Array Science: Implications of Faraday Rotation Measures of Fast Radio Bursts Localized to Host Galaxies

“…We derive estimates of RM host using a similar technique. The ionospheric contributions are estimated using the ionFR Python library, which uses ionospheric data from NASA's Archive of Space Geodesy Data 6 to estimate RM for a given time and line of sight with 12.5 deg 2 resolution (Sotomayor-Beltran et al 2013). The module was modified slightly to account for the change in format of NASA's data files since 2014 to use 1 hr time steps.…”