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Long-term Indian Ocean tsunami record reveals alternating event clusters punctuated by quiet interludes
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  • Jaishri Sanwal,
  • CP Rajendran,
  • Kusala Rajendran
Jaishri Sanwal
Jawaharlal Nehru Centre for Advanced Scientific Research

Corresponding Author:[email protected]

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CP Rajendran
JN Centre for Advanced Scientific Research (JNCASR)
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Jawaharlal Nehru Centre for Advanced Scientific Research
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Kusala Rajendran
Indian Institute of Science
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[ The analyses of sediment cores retrieved near Port Blair (South Andaman) revealed alternate bands of out-of-sequence layers at various depths identified by their sediment characteristics and microfossil content. The ‘out-of-sequence’ layers are found to be in the age ranges of 596-606; 819-856; 1358-1522; 2899-3145; 3718-3461; 4584-4837; 5390-5823; and 6239-6472 yr BP, and show a remarkable chronological equivalence with paleo-tsunami deposits identified from far-field locations in the Indian Ocean region. The long-term tsunami record implies temporally clustered sequence of causative earthquakes alternating with interevent gaps and stand-alone events. This variable recurrence pattern of tsunamigenic great earthquakes is supported by the theoretical models espousing the characteristics of long-term stress re-cycling processes active within the subduction zones and transfer processes between the lower viscoelastic layer and the upper seismogenic crust.]