{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,20]],"date-time":"2026-01-20T03:09:41Z","timestamp":1768878581898,"version":"3.49.0"},"reference-count":44,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2018,6,20]],"date-time":"2018-06-20T00:00:00Z","timestamp":1529452800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Entropy"],"abstract":"<jats:p>We analyse seismicity during the 6-year period 2012\u20132017 in the new time domain termed natural time in the Chiapas region where the M8.2 earthquake occurred, Mexico\u2019s largest earthquake in more than a century, in order to study the complexity measures associated with fluctuations of entropy as well as with entropy change under time reversal. We find that almost three months before the M8.2 earthquake, i.e., on 14 June 2017, the complexity measure associated with the fluctuations of entropy change under time reversal shows an abrupt increase, which, however, does not hold for the complexity measure associated with the fluctuations of entropy in forward time. On the same date, the entropy change under time reversal has been previously found to exhibit a minimum [Physica A 506, 625\u2013634 (2018)]; we thus find here that this minimum is also accompanied by increased fluctuations of the entropy change under time reversal. In addition, we find a simultaneous increase of the Tsallis entropic index q.<\/jats:p>","DOI":"10.3390\/e20060477","type":"journal-article","created":{"date-parts":[[2018,6,20]],"date-time":"2018-06-20T10:41:24Z","timestamp":1529491284000},"page":"477","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":42,"title":["The Complexity Measures Associated with the Fluctuations of the Entropy in Natural Time before the Deadly M\u00e9xico M8.2 Earthquake on 7 September 2017"],"prefix":"10.3390","volume":"20","author":[{"given":"Alejandro","family":"Ram\u00edrez-Rojas","sequence":"first","affiliation":[{"name":"Departamento de Ciencias B\u00e1sicas, Universidad Aut\u00f3noma Metropolitana Azcapotzalco, Av. San Pablo 180, Mexico City 02200, Mexico"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Elsa Leticia","family":"Flores-M\u00e1rquez","sequence":"additional","affiliation":[{"name":"Instituto de Geof\u00edsica, Universidad Nacional Autonoma de Mexico, Mexico City 04510, Mexico"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8483-519X","authenticated-orcid":false,"given":"Nicholas V.","family":"Sarlis","sequence":"additional","affiliation":[{"name":"Section of Solid State Physics and Solid Earth Physics Institute, Department of Physics, National and Kapodistrian University of Athens, Panepistimiopolis, 157 84 Zografos, Greece"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Panayiotis A.","family":"Varotsos","sequence":"additional","affiliation":[{"name":"Section of Solid State Physics and Solid Earth Physics Institute, Department of Physics, National and Kapodistrian University of Athens, Panepistimiopolis, 157 84 Zografos, Greece"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2018,6,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Mega, E.R. 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