author = "Villalobos, C. U. and Bravo, Manuel Alejandro and Ovalle, E. M. 
                         and Foppiano, A. J.",
          affiliation = "{Universidad Adventista de Chile} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)} and {Universidad de Concepci{\'o}n} 
                         and {Universidad de Concepci{\'o}n}",
                title = "Ionospheric characteristics prior to the greatest earthquake in 
                         recorded history",
              journal = "Advances in Space Research",
                 year = "2016",
               volume = "57",
               number = "6",
                pages = "1345--1359",
                month = "Mar.",
             keywords = "Chile, Earthquake precursors, Ionospheric characteristics.",
             abstract = "Although several reports on the variations of some radio observed 
                         ionospheric properties prior to the very large Chile earthquakes 
                         of 21-22 May 1960 have been published, no one up to now has 
                         reported on the variations of simultaneous E- and F-region 
                         characteristics observed at Concepci{\'o}n (36.8S; 73.0W) using 
                         a ground based ionosonde. This paper analyses values of the NmE, 
                         NmEs, h'E, NmF2, h'F, M3000F2 and fmin. Possible solar and 
                         geomagnetic activity effects are first identified and then 
                         anomalies are calculated for all characteristics using reference 
                         values (15-day running medians  interquartile range). Occasions 
                         when anomalies are larger than an upper threshold and less than a 
                         lower threshold are discussed and compared, whenever possible, 
                         with other published studies. Further study is suggested to 
                         unambiguously associate some found possible Es-layer and M3000F2 
                         anomalies with very strong earthquakes.",
                  doi = "10.1016/j.asr.2015.09.015",
                  url = "http://dx.doi.org/10.1016/j.asr.2015.09.015",
                 issn = "0273-1177 and 1879-1948",
             language = "en",
        urlaccessdate = "23 jan. 2021"