Electronic Supplement to
Is the Northern Bay of Bengal Tsunamigenic?

by Harsh K. Gupta and Vineet K. Gahalaut

This supplement contains:

  1. Fig.S1. Color version of Fig.1 in the main text.
  2. Fig.S2. a model of Tsunami generated by the proposed model of 1762 Arakan earthquake.
  3. Relevant pages of Report of Halsted (1843), (first page and relevant 4 pages).
  4. Relevant pages of Report of Oldham (1883), (first page and relevant 2 pages).
  5. Relevant pages of Report of Mallet (1897), (first page and relevant 2 pages).

Figures

Fig.S1. Tectonic setting, bathymetry of the Bay of Bengal and deformation front (Nielsen et al., 2004 and Curray, 2005) in the region. Bathymetry (in m) with blue colors is superimposed on the smoothed relief map of the region. Depth contour of 200 m is also shown. Earthquakes with M>7 (see Data and Resources Section in the main article) are shown by circle with their year of occurrence. The northern part of the 2004 Sumatra-Andaman earthquake rupture in the Andaman region is shown with light red color. The simulated rupture of 600 km x 120 km for the 1762 earthquake is shown by a white color rectangle whose updip edge is placed along the mapped deformation front. An oblique slip of 10 m, direction consistent with the oblique motion in the Indo-Burmese arc (Gahalaut and Gahalaut, 2007; Socquet et al., 2006), produces subsidence (green colors) in the Chittagong region and uplift (red and yellow colour) in the Ramree, Cheduba and Foul Island region. Northern part of the simulated rupture and the deformation front do not extend into the sea, and the southern part of the rupture and the deformation front lies under very shallow water with depth less than 100 m. Simulated rupture lies slightly east of the deformation front in the southern part so as to produce prominent uplift in the Ramree, Cheduba and Foul Island region. The simulated rupture produces only a minor and local tsunami (see Fig.S2).

Figure 1.

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Fig S2. A model of possible tsunami generated by the 1762 Arakan earthquake. We used the rupture model of Fig.S1 with rupture length of 700 km, width 110 km, oblique slip of 10 m, and placed it along the mapped deformation front. We used tsunami code Tunami N2 to estimate the maximum amplitude of tsunami. The generated tsunami is very local and minor and the amplitude decreases quickly in space.

Figure 2.

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Relevant pages of Report of Halsted (1843), (first page and relevant 4 pages).

Halsted Report First Page Halsted Report Relevant Page Halsted Report Relevant Page Halsted Report Relevant Page Halsted Report Relevant Page

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Relevant pages of Report of Oldham (1883), (first page and relevant 2 pages).

Oldham Report First Page Oldham Report Relevant Page Oldham Report Relevant Page

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Relevant pages of Report of Mallet (1897), (first page and relevant 2 pages).

Mallet Report First Page Mallet Report Relevant Pages

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References

Curray, J. R. (2005). Tectonics and history of the Andaman Sea region, J. of Asian Earth Sci. 25, 187–232.

Gahalaut, V. K., and K. Gahalaut (2007). Burma plate motion, J. Geophys. Res. 112, B10402, doi 10.1029/2007JB004928.

Halsted, E. P. (1843). Report on the Island of Chedooba, J. Asiatic Soc. 114, Bengal 319–446.

Mallet, F. R. (1897). Mud volcanoes of Ramri and Chedooba, Geol. Surv.India Records 11, part 2, 188–191.

Nielsen, C., N. Chamot–Rooke, and C. Ranginthe Andaman Cruise Team (2004). From partial to full strain partitioning along the Indo–Burmese hyper-oblique subduction, Mar. Geol. 209, 303–327.

Oldham, (1883). A catalogue of Indian earthquakes, T, Mem. Geol. Surv. India 19, 163–215.

Socquet, A., C. Vigny, N. Chamot–Rooke, W. Simons, C. Rangin, and B. Ambrosius (2007). India and Sunda plates motion and deformation along their boundary in Myanmar determined by GPS, J. Geophys. Res. 111, B05406, doi 10.1029/2005JB003877.


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