Possible Correlations between the ULF Geomagnetic Signature and Mw6.4 Coastal Earthquake, Albania, on 26 November 2019.

Dragoș Armand Stănică,Dumitru Stănică

doi:10.3390/e23020233

Abstract

An earthquake of Mw6.4 hit the coastal zone of Albania on 26 November 2019, at 02:54:11 UTC. It was intensively felt at about 34 km away, in Tirana City, where damages and lives lost occurred. To emphasize a pre-seismic geomagnetic signature before the onset of this earthquake, the data collected on the interval 15 October–30 November 2019, at the Panagjurishte (PAG)-Bulgaria and Surlari (SUA)-Romania observatories were analyzed. Further on, for geomagnetic signal identification we used the polarization parameter (BPOL) which is time invariant in non-seismic conditions and it becomes unstable due to the strain effect related to the Mw6.4earthquake. Consequently, BPOL time series and its standard deviations are performed for the both sites using ultra low frequency (ULF)-fast Fourier transform (FFT) band-pass filtering. A statistical analysis, based on a standardized random variable equation, was applied to emphasize on the BPOL* (PAG) and ABS BPOL* (PAG) time series the anomalous signal’s singularity and, to differentiate the transient local anomalies due to the Mw6.4 earthquake, from the internal and external parts of the geomagnetic field, taken PAG observatory as reference. Finally, the ABS BPOL* (PAG-SUA) time series were obtained on the interval 1–30 November 2019, where a geomagnetic signature greater than 2.0, was detected on 23 November and the lead time was 3 days before the onset of the Mw6.4earthquake.

Highlights

With the aim to identify possible correlation between the pre-seismic geomagnetic signature and the coastal Mw6.4earthquake, in this paper we investigated the geomagnetic data recorded, on the interval 15 October–30 November, 2019, at the Panagjurishte (PAG), Bulgaria and Surlari (SUA), Romania, the first one taken as reference, and the following results are inferred as:
— The BPOL (PAG) and BPOL (SUA) time series obtained on the interval 1–30 November using (Relation 1), emphasize two pre-seismic anomalous signatures, extended on the intervals 21–27 November for PAG and 21–28 November for SUA, on which two maximum amplitudes were identified on 23 November (1.727 for PAG and 1.892 for SUA), with 3 days before the occurrence of Mw6.4earthquake
— A precursory signature associated to the above-mentioned earthquake was identified on the BPOL* (PAG) and ABS BPOL* (PAG) time series carried out on the interval 1–30 November, using a statistical analysis based on Relation 3, and the results are emphasized in Section 3.2, Figures 6 and 7

Summary

Introduction

The results carried out using ground-based geomagnetic data and ionospheric perturbations, associated with the catastrophic earthquakes Mw9.0 Tohoku, Japan on March 2011, Mw8.3 Coquimbo, Chile on September 2015 and Mw8.1Chiapas-Mexico, on September 2017 and the Vrancea seismicity, Romania, give useful information to elaborate a specific methodology able to emphasize possible inter-relations between the pre-seismic ultralow frequency (ULF) anomalous geomagnetic signature and the above-mentioned earthquakes [1,2,3,4,5,6,7,8,9,10], taking into account the following three possible earthquake generation mechanisms [11]: (a) piezomagnetic effect [12]; (b) magneto-hydrodynamic effect [13]; (c) Electrokinetic effect [14,15]. As regards the Mw 6.4 earthquake analysis, the following previously contributions at the EGU2020 “Sharing Geosphere Online” are briefly presented further on: a multi parameters analysis of satellite and ground based data (satellite thermal anomalies, atmospheric chemical potential, radon level variation, and very high frequency (VHF) propagation in lower atmosphere) which may supply significant information before an earthquake [16]; a statistical analysis applied to identify a precursory anomaly in the total electron content [17]; observations related to the lower ionospheric turbulence variations in the last half of 2019, in broader Balkan region [18]; INFREP Radio Network revealed variations in connection with six earthquakes (Mw > 5.0) occurred in the Balkan Peninsula and Adriatic Sea on 26 and 27 November 2019 [19]; information regarding the pre-earthquake ionospheric anomalies by using the Romanian VLF/LF Infrep receivers. Entropy 2021, 23, 233 Entropy 2021, 23, 233 occurred in the Balkan Peninsula and Adriatic Sea on 26 and 27 November 2019 [19]2;oifn9formation regarding the pre-earthquake ionospheric anomalies by using the Romanian VLF/LF Infrep receivers and Gnss Global European Networks [20]; the results carried out amfbn[r2nyiao1qdm]nut.hGieeAte-wonTlrssloIiasRntrthGkgeialsloolnoiffitobneaBmafaltomahlErklemuiuaerlrmnastoitpiraipnoealegnramtaihnoimnoenNncefrbirteetryatoaiwmcrsmieosneseyrwgaksonotsouersf[rmk2oBk0foaa]nrf;lrookteahwbaeeunmlmesrurdtepelssghtguaieiaptloetsaasnlibrlzciaoebtameudyrtrteieimttnecrhdihe[ec2ano1onsiuq]yrs.tiusgoAtbeiefyn-lmTlrtootIhhRfabeirutsaehssnaietentomefdsmolailprftiaftemhleelialreatisesthtineizeiotnertnmdeptchiranhieenl--csreeisamseiscosuigrnkanloswaslesodcgieataebdouwtitthhethoerigaibnoovfe-tmheednitfifoenreendtcpartea-ssteriospmhiiccseiganrtahlqs uaasskoecsiaatnedd,wsuitbhtsheequaebnotvlye-,minenthtiiosnsetuddcya,tatshterodpahtaicceoalrlethctqeudakfreosmantdh,estuwbosegqeuoemntalgy,nientitchoisbssteurdvay,tothrieesdaPtaacnoalglejuctreisdhtfero(mPAtGhe), tBwuolggaerioamaangdneStuicrloarbise(SrvUaAto),riResomPaannaiagjwureirsehtaen(aPlyAzGed), Binulcgoarrriealaatinodn SwuirthlarMi (wSU6.A4e)a, rRthoqmuaankiea.wFuerrethaenraolynz, etod dinifcfeorrerneltaiatitoenawpirteh-sMeiwsm6i.4ceaanrothmqaulaokues. sFiugnrtahlearsoson-, tcoiadteifdfewreinthtiattheisaeparret-hsqeiusamkiec, aansotmatiasltoiucaslsaignnaalyl saisssboacisaetdedonwtihthetshtiasnedaarrthdqizueadkera, nadstoamtisvtiacrailaanbalelyesqisuabtaisoend, toankethneosbtsaenrdvaartdorizyePdAraGnadsormefveraerniacbel,eweaqsuaaptiponli,edta.kFeinnaolblys,eirtvmatuorsyt bPeAmGeansrteiofenreedncthe,awt aans aapnpolmieadl.ouFisnianltley,rvitaml, uhsatvbinegmaenntaipoenxedonth2a3t aNnoavneommbaelro, u2s01in9toernvaalll, hthaevifnoglalonwaipnegxtiomne23seNrieosveomf BbPerO, L20(1P9AoGn),alBlPtOheL*fo(lPloAwGin),gAtBimS eBsPeOriLe*s (oPfABGP)O, Lan(dPAAGB)S, BBPPOOLL** ((PPAAGG)-,SAUBAS)BwPaOsLi*de(PnAtiGfie),da,nwditAhB3SdBaPyOs Lb*ef(oPrAeGth-SeUeAar)thwqausaikdeenotcicfiuerdr,ewnciteho3nd2a6yNs boevfeomretbheer,e2a0r1th9q. uake occurrence on 26 November, 2019

Methods

Results

Conclusion