• P-ISSN 0974-6846 E-ISSN 0974-5645

Indian Journal of Science and Technology


Indian Journal of Science and Technology

Year: 2023, Volume: 16, Issue: 8, Pages: 557-569

Original Article

Seismotectonics of Andaman-Sumatra Region: Seismic Quiescence and B Value as Possible Precursors

Received Date:15 December 2022, Accepted Date:25 January 2023, Published Date:27 February 2023


Objectives: a) To analyze the long-term seismicity and understand the potential of seismic quiescence study to use it as a reliable seismic precursor b) To estimate B value and understand the variation in B value as earthquake precursor in seismically active region. Methods: The present study analyses the seismicity pattern from the Andaman- Sumatra region for a period of 1964 to 2018. The area has been divided into epicentral blocks. Earthquakes preceding and succeeding a major earthquake with different seismic phases of quiescence and pattern of seismicity have been studied carefully. All quiescence periods are characterized by high b values and period of major shocks has a low b value. Main shock events for each epicentral block with different phases of quiescence (Q1, Q2 and Q3) and active seismicity have been identified and analyzed. Findings: The study suggests that there is generally approximately 6-12 years of gap between major earthquakes. There are 28 years of quiescence before the major earthquake of the stature of Dec 26, 2004 mega earthquake, suggesting that long term quiescence leads to great earthquakes. The study also proposes that the area between 20 and 60N latitudes shows a long-term quiescence which may lead to a major earthquake in the near future. A thorough analysis of long-term seismicity and seismic quiescence can be used as an earthquake precursor, though with limitations. The latest post seismic quiescence period Q2 after the greater events of 2004 and 2005, may yield an impending event of 6.5 M or even greater. Novelty: The present study deals with the precursor studies of one of the most important tectonic zone. Extensive analysis of 54 Years of data has been done and the scope of using seismicity and b value for the long-term prediction of earthquakes has been examined. The periodicity of seismicity has been used to quantify the precursors. Though various statistical studies have been attempted for this zone, methodology adopted here proved one of the reliable methods to check for the possible mega earthquakes of this seismically active zone, which can be applied to other seismically active areas as well.

Keywords: Seismicity; Andaman-Sumatra; Seismic quiescence; B-value; Precursors


  1. Mukhopadhyay B, Mukhopadhyay M, Mishra OP, Sengupta D, Dasgupta S, Elawadi E, et al. Constraining the Seismic Potentiality Analysis for Andaman Arc System, NE Indian Ocean. Journal of the Geological Society of India. 2018;91(5):523–534. Available from: https://doi.org/10.1007/s12594-018-0900 -3
  2. Joseph RC. Tectonics and history of the Andaman Sea region. Journal of Asian Earth Sciences. 2005;2005(25):187–232. Available from: https://doi.org/10.1016/j.jseaes.2004.09.001
  3. Aswini KK, Raju KAK, Dewangan P, Yatheesh VV, Singha P, Reddy TR. Seismotectonic evaluation of off Nicobar earthquake swarms, Andaman Sea. Journal of Asian Earth Sciences. 2021;221(104948). Available from: https://doi.org/10.1016/j.jseaes.2021.104948
  4. Katili JA. Volcanism and plate tectonics in the Indonesian island arcs. Tectonophysics. 1975;26(3-4):165–188. Available from: https://doi.org/10.1016/0040-1951(75)90088-8
  5. Kerry S, Natawidjaja D. Neotectonics of Sumatra fault, Indonesia. Journal of Geophysical Research. 2000;28(105):295–323. Available from: https://authors.library.caltech.edu/21722/1/Sieh2000p28295_Jour_Geophys_Res.pdf
  6. Lasitha S, Radhakrishna M, Sanu T. Seismically active deformation in the Sumatra-Java trench-arc region: geodynamic implications. Current Science. 2006;5(90):690–695. Available from: https://www.currentscience.ac.in/Volumes/90/05/0690.pdf
  7. Radhakrishna M, Lasitha S, Mukhopadhyay M. Seismicity, gravity anomalies and lithospheric structure of the Andaman arc, NE Indian Ocean. Tectonophysics. 2008;460(1-4):248–262. Available from: https://doi.org/10.1016/j.tecto.2008.08.021
  8. Livio C, Piergiorgio P, Sotgiu A. A Critical Review of Ground Based Observations of Earthquake Precursors. Frontiers in Earth Science. 2021;9:1–30. Available from: https://doi.org/10.3389/feart.2021.676766
  9. Basab M, Sujit D. Seismic hazard assessment of Kashmir and Kangra valley region, Western Himalaya, India. Geomatics, Natural Hazards and Risk. 2015;6(2):149–183. Available from: https://doi.org/10.1080/19475705.2013.832405
  10. Sujit D, Basab M. Earthquake Forerunner as Probable Precursor - An Example from North Burma Subduction Zone. J. of Geological society of India. 2012;(80) 393–402. Available from: https://doi.org/10.1007/s12594-012-0157-1
  11. CHS. Mechanisms of Seismic Quiescence. PAGEOPH. 1988;(126) 701–718. Available from: https://doi.org/10.1007/BF00879016
  12. Gutenberg B, Richter CF. Frequency of earthquakes in California*. Bulletin of the Seismological Society of America. 1944;34(4):185–188. Available from: https://www.scirp.org/(S(351jmbntvnsjt1aadkposzje))/reference/ReferencesPapers.aspx?ReferenceID=1863453
  13. Schorlemmer D, Wiemer S, Wyss M. Variations in earthquake-size distribution across different stress regimes. Nature. 2005;437(7058):539–542. Available from: https://doi.org/10.1038/nature04094
  14. Hatzidimitriou PM, Papadimitriou EE, Mountrakis DM, Papazachos BC. The seismic parameter b of the frequency-magnitude relation and its association with the geological zones in the area of Greece. Tectonophysics. 1985;(120) 141–151. Available from: https://doi.org/10.1016/0040-19518590092-7 .
  15. Tasapanos T. b-Values of two tectonic parts in the circum-pacific belt. PAGEOPH. 1990;134(2):229–242. Available from: https://doi.org/10.1007/BF00876999
  16. Kanamori H. The Nature of Seismicity Patterns Before Large Earthquakes. In: DWS, PGR., eds. Earthquake Prediction: An International Review Maurice Ewing Series . (Vol. 4, pp. 1-19) American Geophysical Union. 1981.
  17. Katsumata Kei A. Long-Term Seismic Quiescence before the 2004 Sumatra Mw 9.1 Earthquake. Bulletin of the Seismological Society of America. 2015;(105).


© 2023 Anjana & Lasitha. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Published By Indian Society for Education and Environment (iSee)


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