We present a comprehensive multi-parametric analysis of Lithosphere-Atmosphere-Ionosphere Coupling (LAIC) processes associated with the 24 January 2018 Aomori earthquake (
), located off the east coast of northern Honshu, Japan. Thermal observations reveal coherent pre-seismic irregularities in near-surface air temperature, relative humidity, and atmospheric chemical potential (ACP), with notable variations emerging 1 - 2 days prior to the event, followed by co-seismic intensification and rapid post-seismic relaxation. Acoustic channel analysis indicates enhanced atmospheric gravity wave (AGW) activity derived from ERA5 reanalysis, with significant amplification beginning 3 - 5 days before the earthquake, peaking around the event time, and gradually diminishing afterward. Electromagnetic and ionospheric signatures are evident in both lower and upper atmospheric regions. Very-Low-Frequency (VLF/LF) sub-ionospheric observations exhibit statistically significant pre-seismic anomalies, particularly one day prior to the earthquake, while GNSS-based Vertical Total Electron Content (VTEC) shows clear enhancements during the preparatory phase and maximum deviation on the earthquake day. Global Ionospheric Map (GIM) analysis further confirms localized ionospheric perturbations centered around the epicentral region, with a clear spatial decay away from the source. All observations were obtained under geomagnetically quiet conditions, ensuring minimal external influence. Together, these thermal, acoustic, and electromagnetic signatures indicate a consistent sequence of pre-seismic build-up, co-seismic response, and post-seismic recovery, providing a robust multi-channel imprint of the Aomori earthquake and highlighting the importance of integrated multi-parametric approaches for understanding earthquake preparatory processes.
References
[1]
Freund, F. (2011) Pre-Earthquake Signals: Underlying Physical Processes. Journal of Asian Earth Sciences, 41, 383-400. https://doi.org/10.1016/j.jseaes.2010.03.009
[2]
Sasmal, S., Chowdhury, S., Kundu, S., Politis, D.Z., Potirakis, S.M., Balasis, G., et al. (2021) Pre-Seismic Irregularities during the 2020 Samos (Greece) Earthquake (M = 6.9) as Investigated from Multi-Parameter Approach by Ground and Space-Based Techniques. Atmosphere, 12, Article 1059. https://doi.org/10.3390/atmos12081059
[3]
Pulinets, S. and Ouzounov, D. (2011) Lithosphere-Atmosphere-Ionosphere Coupling (LAIC) Model—An Unified Concept for Earthquake Precursors Validation. Journal of Asian Earth Sciences, 51, 1139-1152.
[4]
Liu, J.Y., Chen, C.H., Lin, C.H., Tsai, H.F., Chen, C.H. and Kamogawa, M. (2011) Ionospheric Disturbances Triggered by the 11 March 2011 M9.0 Tohoku Earthquake. JournalofGeophysicalResearch: SpacePhysics, 116, A06319. https://doi.org/10.1029/2011ja016761
[5]
Hayakawa, M., Molchanov, O.A., Ondoh, T. and Kawai, E. (1996) The Precursory Signature Effect of the Kobe Earthquake on VLF Sub-Ionospheric Signals. Journal of the Communications Research Laboratory, 43, 169-180.
[6]
Clilverd, M.A., Rodger, C.J. and Thomson, N.R. (1999) Investigating Seismoionospheric Effects on a Long Subionospheric Path. JournalofGeophysicalResearch: SpacePhysics, 104, 28171-28179. https://doi.org/10.1029/1999ja900285
[7]
Pulinets, S. and Boyarchuk, K. (2004) Ionospheric Precursors of Earthquakes. Springer.
[8]
Liu, D. (2000) Anomalies Analyses on Satellite Remote Sensing OLR before ChiChi Earthquake of Taiwan Province. Geographic Information Science, 2, 33-36.
[9]
Ghosh, S., Chowdhury, S., Kundu, S., Sasmal, S., Politis, D.Z., Potirakis, S.M., et al. (2022) Unusual Surface Latent Heat Flux Variations and Their Critical Dynamics Revealed before Strong Earthquakes. Entropy, 24, Article 23. https://doi.org/10.3390/e24010023
[10]
Chakraborty, S., Sasmal, S., Chakrabarti, S.K. and Bhattacharya, A. (2018) Observational Signatures of Unusual Outgoing Longwave Radiation (OLR) and Atmospheric Gravity Waves (AGW) as Precursory Effects of May 2015 Nepal Earthquakes. JournalofGeodynamics, 113, 43-51. https://doi.org/10.1016/j.jog.2017.11.009
[11]
Gorny, V., Salman, A.G., Tronin, A.A. and Shilin, B.V. (1998) The Earth’s Outgoing IR Radiation as an Indicator of Seismic Activity. Proceedings of the Academy of Sciences of the USSR, 301, 67-69.
[12]
Ghosh, S., Sasmal, S., Maity, S.K., Potirakis, S.M. and Hayakawa, M. (2024) Thermal Anomalies Observed during the Crete Earthquake on 27 September 2021. Geosciences, 14, Article 73. https://doi.org/10.3390/geosciences14030073
[13]
Ouzounov, D. and Freund, F. (2004) Mid-Infrared Emission Prior to Strong Earthquakes Analyzed by Remote Sensing Data. Advances in Space Research, 33, 268-273. https://doi.org/10.1016/s0273-1177(03)00486-1
[14]
Tronin, A.A., Hayakawa, M. and Molchanov, O.A. (2002) Thermal IR Satellite Data Application for Earthquake Research in Japan and China. Journal of Geodynamics, 33, 519-534. https://doi.org/10.1016/s0264-3707(02)00013-3
[15]
Fu, H., Hsiao, L., Yu, X., Lin, C. and Lin, M. (2020) OLR Variability Prior to M ≥ 6 Earthquakes in Taiwan Region. Frontiers in Earth Science, 8, Article 364.
[16]
Saraf, A.K., Choudhury, S., Rawat, V., Das, J.D., et al. (2008) Satellite Detection of Thermal Anomalies Associated with Earthquakes: A Study of Iranian Events. Natural Hazards, 47, 119-135.
[17]
Zhang, H., Zhu, K., Cheng, Y., Marchetti, D., Chen, W., Fan, M., et al. (2023) Atmospheric and Ionospheric Effects of La Palma Volcano 2021 Eruption. Atmosphere, 14, Article 1198. https://doi.org/10.3390/atmos14081198
[18]
Korepanov, V., Hayakawa, M., Yampolski, Y. and Lizunov, G. (2009) AGW as a Seismo-Ionospheric Coupling Responsible Agent. Physics and Chemistry of the Earth, Parts A/B/C, 34, 485-495. https://doi.org/10.1016/j.pce.2008.07.014
[19]
Thurairajah, B., Bailey, S.M., Cullens, C.Y., Hervig, M.E. and Russell, J.M. (2014) Gravity Wave Activity during Recent Stratospheric Sudden Warming Events from SOFIE Temperature Measurements. Journal of Geophysical Research: Atmospheres, 119, 8091-8103. https://doi.org/10.1002/2014jd021763
[20]
Chakraborty, S., Sasmal, S., Basak, T., Ghosh, S., Palit, S., Chakrabarti, S.K., et al. (2017) Numerical Modeling of Possible Lower Ionospheric Anomalies Associated with Nepal Earthquake in May, 2015. Advances in Space Research, 60, 1787-1796. https://doi.org/10.1016/j.asr.2017.06.031
[21]
Yang, S., Asano, T. and Hayakawa, M. (2019) Abnormal Gravity Wave Activity in the Stratosphere Prior to the 2016 Kumamoto Earthquakes. Journal of Geophysical Research: Space Physics, 124, 1410-1425. https://doi.org/10.1029/2018ja026002
[22]
Piersanti, M., Materassi, M., Battiston, R., Carbone, V., Cicone, A., D’Angelo, G., etal. (2020) Magnetospheric-Ionospheric-Lithospheric Coupling Model. 1: Observations during the 5 August 2018 Bayan Earthquake. Remote Sensing, 12, Article 3299. https://doi.org/10.3390/rs12203299
[23]
Hayakawa, M., Schekotov, A., Izutsu, J. and Nickolaenko, A.P. (2019) Seismogenic Effects in ULF/ELF/VLF Electromagnetic Waves. International Journal of Electronics and Applied Research, 6, 1-86. https://doi.org/10.33665/ijear.2019.v06i02.001
[24]
Schekotov, A., Molchanov, O., Hattori, K., Fedorov, E., Gladyshev, V.A., Belyaev, G.G., et al. (2006) Seismo-Ionospheric Depression of the ULF Geomagnetic Fluctuations at Kamchatka and Japan. Physics and Chemistry of the Earth, Parts A/B/C, 31, 313-318. https://doi.org/10.1016/j.pce.2006.02.043
[25]
Chowdhury, S., Kundu, S., Ghosh, S., Hayakawa, M., Schekotov, A., Potirakis, S.M., et al. (2022) Direct and Indirect Evidence of Pre-Seismic Electromagnetic Emissions Associated with Two Large Earthquakes in Japan. Natural Hazards, 112, 2403-2432. https://doi.org/10.1007/s11069-022-05271-5
[26]
Hayakawa, M., Schekotov, A., Izutsu, J., Nickolaenko, A.P. and Hobara, Y. (2023) Seismogenic ULF/ELF Wave Phenomena: Recent Advances and Future Perspectives. Open Journal of Earthquake Research, 12, 45-113. https://doi.org/10.4236/ojer.2023.123003
[27]
Anagnostopoulos, G.C., Karanikola, I. and Marhavilas, P. (2001) Large-Scale Energetic Particle Layers in the High Latitude Jovian Magnetosphere. Planetary and Space Science, 49, 1049-1065. https://doi.org/10.1016/s0032-0633(01)00019-8
[28]
Chakraborty, S., Sasmal, S., Basak, T. and Chakrabarti, S.K. (2019) Comparative Study of Charged Particle Precipitation from Van Allen Radiation Belts as Observed by NOAA Satellites during a Land Earthquake and an Ocean Earthquake. Advances in Space Research, 64, 719-732. https://doi.org/10.1016/j.asr.2019.05.020
[29]
Fidani, C. (2015) Particle Precipitation Prior to Large Earthquakes of Both the Sumatra and Philippine Regions: A Statistical Analysis. Journal of Asian Earth Sciences, 114, 384-392. https://doi.org/10.1016/j.jseaes.2015.06.010
[30]
Sasmal, S. and Chakrabarti, S.K. (2009) Ionosperic Anomaly Due to Seismic Activities—Part 1: Calibration of the VLF Signal of VTX 18.2 kHz Station from Kolkata and Deviation during Seismic Events. Natural Hazards and Earth System Sciences, 9, 1403-1408. https://doi.org/10.5194/nhess-9-1403-2009
[31]
Kasahara, Y., Muto, F., Horie, T., Yoshida, M., Hayakawa, M., Ohta, K., et al. (2008) On the Statistical Correlation between the Ionospheric Perturbations as Detected by Subionospheric VLF/LF Propagation Anomalies and Earthquakes. Natural Hazards and Earth System Sciences, 8, 653-656. https://doi.org/10.5194/nhess-8-653-2008
[32]
Ray, S., Chakrabarti, S.K., Mondal, S.K. and Sasmal, S. (2011) Ionospheric Anomaly Due to Seismic Activities-III: Correlation between Night Time VLF Amplitude Fluctuations and Effective Magnitudes of Earthquakes in Indian Sub-Continent. Natural Hazards and Earth System Sciences, 11, 2699-2704. https://doi.org/10.5194/nhess-11-2699-2011
[33]
Chakrabarti, S.K., Sasmal, S. and Chakrabarti, S. (2010) Ionospheric Anomaly Due to Seismic Activities—Part 2: Evidence from D-Layer Preparation and Disappearance Times. Natural Hazards and Earth System Sciences, 10, 1751-1757. https://doi.org/10.5194/nhess-10-1751-2010
[34]
Sasmal, S., Chakrabarti, S.K., Chakrabarti, S. and Chakrabarti, S.K. (2010) Studies of the Correlation between Ionospheric Anomalies and Seismic Activities in the Indian Subcontinent. AIP Conference Proceedings, 1286, 270-290. https://doi.org/10.1063/1.3512885
[35]
Maurya, A.K., Venkatesham, K., Tiwari, P., Vijaykumar, K., Singh, R., Singh, A.K., etal. (2016) The 25 April 2015 Nepal Earthquake: Investigation of Precursor in VLF Subionospheric Signal. Journal of Geophysical Research: Space Physics, 121, 10403-10416. https://doi.org/10.1002/2016ja022721
[36]
Hayakawa, M., Kasahara, Y., Nakamura, T., Hobara, Y., Rozhnoi, A., Solovieva, M., et al. (2010) On the Correlation between Ionospheric Perturbations as Detected by Subionospheric VLF/LF Signals and Earthquakes as Characterized by Seismic Intensity. Journal of Atmospheric and Solar-Terrestrial Physics, 72, 982-987. https://doi.org/10.1016/j.jastp.2010.05.009
[37]
Sasmal, S., Chakrabarti, S.K. and Ray, S. (2014) Unusual Behavior of Very Low Frequency Signal during the Earthquake at Honshu/Japan on 11 March, 2011. Indian Journal of Physics, 88, 1013-1019. https://doi.org/10.1007/s12648-014-0520-8
[38]
Hayakawa, M., Hobara, Y., Yasuda, Y., Yamaguchi, H., Ohta, K., Izutsu, J., et al. (2012) Possible Precursor to the March 11, 2011, Japan Earthquake: Ionospheric Perturbations as Seen by Subionospheric Very Low Frequency/Low Frequency Propagation. Annals of Geophysics, 55, 95-99. https://doi.org/10.4401/ag-5357
[39]
Pal, P., Sasmal, S. and Chakrabarti, S.K. (2017) Studies of Seismo-Ionospheric Correlations Using Anomalies in Phase of Very Low Frequency Signal. Geomatics, Natural Hazards and Risk, 8, 167-176. https://doi.org/10.1080/19475705.2016.1161666
[40]
Politis, D.Z., Potirakis, S.M., Contoyiannis, Y.F., Biswas, S., Sasmal, S. and Hayakawa, M. (2021) Statistical and Criticality Analysis of the Lower Ionosphere Prior to the 30 October 2020 Samos (Greece) Earthquake (M6.9), Based on VLF Electromagnetic Propagation Data as Recorded by a New VLF/LF Receiver Installed in Athens (Greece). Entropy, 23, Article 676. https://doi.org/10.3390/e23060676
[41]
Kumar, S., Kumar, S. and Kumar, A. (2022) Earthquakes Associated Subionospheric VLF Anomalies Recorded at Two Low Latitude Stations in the South Pacific Region. Journal of Atmospheric and Solar-Terrestrial Physics, 229, Article 105834. https://doi.org/10.1016/j.jastp.2022.105834
[42]
Politis, D.Z., Sasmal, S., Hayakawa, M., Haralambous, H., Datta, A. and Potirakis, S.M. (2024) A Six-Year (2014-2020) Statistical Correlation Study of VLF Terminator Time Shift with Earthquakes in Japan. Remote Sensing, 16, Article 4162. https://doi.org/10.3390/rs16224162
[43]
Mannucci, A.J., Wilson, B.D. and Edwards, C.D. (1993) A New Method for Monitoring the Earth’s Ionospheric Total Electron Content Using the GPS Global Network. Proceedings of the Institute of Navigation, Salt Lake City, 20-22 January 1993, 1323-1332.
Liu, J.Y., Chen, Y.I., Chuo, Y.J. and Tsai, H.F. (2001) Variations of Ionospheric Total Electron Content during the Chi-Chi Earthquake. Geophysical Research Letters, 28, 1383-1386. https://doi.org/10.1029/2000gl012511
[46]
Langley, R., Fedrizzi, M., Paula, E., Santos, M. and Komjathy, A. (2002) Mapping the Low Latitude Ionosphere with GPS. GPS World, 13, 41-46.
[47]
Liu, J.Y., Chen, Y.I., Chen, C.H., Liu, C.Y., Chen, C.Y., Nishihashi, M., et al. (2009) Seismoionospheric GPS Total Electron Content Anomalies Observed before the 12 May 2008 Mw7.9 Wenchuan Earthquake. JournalofGeophysicalResearch: SpacePhysics, 114, A04320. https://doi.org/10.1029/2008ja013698
[48]
Ho, Y.Y., Jhuang, H.K., Su, Y.C. and Liu, J.Y. (2013) Seismo-Ionospheric Anomalies in Total Electron Content of the GIM and Electron Density of DEMETER before the 27 February 2010 M8.8 Chile Earthquake. AdvancesinSpaceResearch, 51, 2309-2315. https://doi.org/10.1016/j.asr.2013.02.006
[49]
Kumar, S. and Singh, A.K. (2017) Ionospheric Precursors Observed in TEC Due to Earthquake of Tamenglong on 3 January 2016. Current Science, 113, 795-801. https://doi.org/10.18520/cs/v113/i04/795-801
[50]
Oikonomou, C., Haralambous, H. and Muslim, B. (2016) Investigation of Ionospheric TEC Precursors Related to the M7.8 Nepal and M8.3 Chile Earthquakes in 2015 Based on Spectral and Statistical Analysis. Natural Hazards, 83, 97-116. https://doi.org/10.1007/s11069-016-2409-7
[51]
De Santis, A., De Franceschi, G., Spogli, L., Perrone, L., Alfonsi, L., Qamili, E., et al. (2015) Geospace Perturbations Induced by the Earth: The State of the Art and Future Trends. Physics and Chemistry of the Earth, Parts A/B/C, 85, 17-33. https://doi.org/10.1016/j.pce.2015.05.004
[52]
Sasmal, S., Chowdhury, S., Kundu, S., Ghosh, S., Politis, D., Potirakis, S., et al. (2023) Multi-parametric Study of Seismogenic Anomalies during the 2021 Crete Earthquake (M = 6.0). Annals of Geophysics, 66, SE646. https://doi.org/10.4401/ag-8992
[53]
Ghosh, S., Sasmal, S., Midya, S.K. and Chakrabarti, S.K. (2017) Unusual Change in Critical Frequency of F2 Layer during and Prior to Earthquakes. Open Journal of Earthquake Research, 6, 191-203. https://doi.org/10.4236/ojer.2017.64012
[54]
Yang, S.S., Potirakis, S.M., Sasmal, S. and Hayakawa, M. (2020) Natural Time Analysis of Global Navigation Satellite System Surface Deformation: The Case of the 2016 Kumamoto Earthquakes. Entropy, 22, Article 674. https://doi.org/10.3390/e22060674
[55]
Ghosh, S., Sasmal, S., Naja, M., Potirakis, S. and Hayakawa, M. (2022) Study of Aerosol Anomaly Associated with Large Earthquakes. Advances in Space Research, 71, 129-143.
[56]
Hayakawa, M., Izutsu, J., Schekotov, A., Yang, S., Solovieva, M. and Budilova, E. (2021) Lithosphere-Atmosphere-Ionosphere Coupling Effects Based on Multiparameter Precursor Observations for February-March 2021 Earthquakes (M~7) in the Offshore of Tohoku Area of Japan. Geosciences, 11, Article 481. https://doi.org/10.3390/geosciences11110481
[57]
Wu, L., Qi, Y., Mao, W., Lu, J., Ding, Y., Peng, B., et al. (2023) Scrutinizing and Rooting the Multiple Anomalies of Nepal Earthquake Sequence in 2015 with the Deviation-Time-Space Criterion and Homologous Lithosphere-Coversphere-Atmosphere-Ionosphere Coupling Physics. Natural Hazards and Earth System Sciences, 23, 231-249. https://doi.org/10.5194/nhess-23-231-2023
[58]
Marchetti, D., De Santis, A., D’Arcangelo, S., Poggio, F., Piscini, A., A. Campuzano, S., et al. (2019) Pre-Earthquake Chain Processes Detected from Ground to Satellite Altitude in Preparation of the 2016-2017 Seismic Sequence in Central Italy. Remote Sensing of Environment, 229, 93-99. https://doi.org/10.1016/j.rse.2019.04.033
[59]
Ouzounov, D., Pulinets, S., Davidenko, D., Rozhnoi, A., Solovieva, M., Fedun, V., etal. (2021) Transient Effects in Atmosphere and Ionosphere Preceding the 2015 M7.8 and M7.3 Gorkha-Nepal Earthquakes. Frontiers in Earth Science, 9, Article 757358. https://doi.org/10.3389/feart.2021.757358
[60]
Chetia, T., Sharma, G., Dey, C. and Raju, P.L.N. (2020) Multi-Parametric Approach for Earthquake Precursor Detection in Assam Valley (Eastern Himalaya, India) Using Satellite and Ground Observation Data. Geotectonics, 54, 83-96. https://doi.org/10.1134/s0016852120010045
[61]
Hayakawa, M., Schekotov, A., Izutsu, J., Yang, S., Solovieva, M. and Hobara, Y. (2022) Multi-Parameter Observations of Seismogenic Phenomena Related to the Tokyo Earthquake (M = 5.9) on 7 October 2021. Geosciences, 12, Article 265. https://doi.org/10.3390/geosciences12070265
[62]
Zhang, Y., Wang, T., Chen, W., Zhu, K., Marchetti, D., Cheng, Y., et al. (2023) Are There One or More Geophysical Coupling Mechanisms before Earthquakes? The Case Study of Lushan (China) 2013. Remote Sensing, 15, Article 1521. https://doi.org/10.3390/rs15061521
[63]
Dobrovolsky, I.P., Zubkov, S.I. and Miachkin, V.I. (1979) Estimation of the Size of Earthquake Preparation Zones. Pure and Applied Geophysics, 117, 1025-1044. https://doi.org/10.1007/bf00876083
[64]
Fritts, D.C. and Alexander, M.J. (2003) Gravity Wave Dynamics and Effects in the Middle Atmosphere. Reviews of Geophysics, 41, 1-64. https://doi.org/10.1029/2001rg000106
[65]
Seemala, G.K. and Valladares, C.E. (2011) Statistics of Total Electron Content Depletions Observed over the South American Continent for the Year 2008. Radio Science, 46, RS5019. https://doi.org/10.1029/2011rs004722
[66]
Seemala, G.K. (2023) Estimation of Ionospheric Total Electron Content (TEC) from GNSS Observations. In: AtmosphericRemoteSensing, Elsevier, 63-84. https://doi.org/10.1016/b978-0-323-99262-6.00022-5
[67]
Klotz, S. and Johnson, N.L. (1983) Encyclopedia of Statistical Sciences. Wiley.
[68]
Liu, J., Zhang, X., Novikov, V. and Shen, X. (2016) Variations of Ionospheric Plasma at Different Altitudes before the 2005 Sumatra Indonesia Ms 7.2 Earthquake. Journal of Geophysical Research: Space Physics, 121, 9179-9187. https://doi.org/10.1002/2016ja022758
[69]
Pulinets, S., Krankowski, A., Hernandez-Pajares, M., Marra, S., Cherniak, I., Zakharenkova, I., et al. (2021) Ionosphere Sounding for Pre-Seismic Anomalies Identification (INSPIRE): Results of the Project and Perspectives for the Short-Term Earthquake Forecast. FrontiersinEarthScience, 9, Article 610193. https://doi.org/10.3389/feart.2021.610193
[70]
Tariq, M.A., Shah, M., Hernández-Pajares, M. and Iqbal, T. (2019) Pre-Earthquake Ionospheric Anomalies before Three Major Earthquakes by GPS-TEC and GIM-TEC Data during 2015-2017. AdvancesinSpaceResearch, 63, 2088-2099. https://doi.org/10.1016/j.asr.2018.12.028
[71]
Hayakawa, M., Solovieva, M., Kopylova, G., Hirooka, S., Sasmal, S., Nanda, K., et al. (2025) Multi-Parameter and Multi-Layer Observations of Electromagnetic Precursors to a Huge Hokkaido Earthquake (M = 6.7) on 5 September, 2018, and Lithosphere-Atmosphere-Ionosphere Coupling Channel. Atmosphere, 16, Article 1372. https://doi.org/10.3390/atmos16121372
[72]
Sasmal, S., Nanda, K., Hayakawa, M., Solovieva, M., Kopylova, G. and Potirakis, S.M. (2025) Towards Understanding Earthquake Preparatory Dynamics: A Multi-Parametric Investigation of the 2025 Kamchatka Mw 8.8 Event. Atmosphere, 16, Article 1328. https://doi.org/10.3390/atmos16121328
[73]
Scholz, C.H. (2002). The Mechanics of Earthquakes and Faulting. 2nd Edition, Cambridge University Press. https://doi.org/10.1017/cbo9780511818516
[74]
Brace, W.F. and Byerlee, J.D. (1966) Stick-Slip as a Mechanism for Earthquakes. Science, 153, 990-992. https://doi.org/10.1126/science.153.3739.990
[75]
Kanamori, H. (1977) The Energy Release in Great Earthquakes. Journal of Geophysical Research, 82, 2981-2987. https://doi.org/10.1029/jb082i020p02981
