TY - GEN
T1 - Boulder transport by the 2004 Indian Ocean tsunami
T2 - 34th IAHR Congress 2011 - Balance and Uncertainty: Water in a Changing World, Incorporating the 33rd Hydrology and Water Resources Symposium and the 10th Conference on Hydraulics in Water Engineering
AU - Nandasena, N. A.K.
AU - Tanaka, Norio
AU - Paris, Raphaël
N1 - Publisher Copyright:
© 34th IAHR Congress 2011. All rights reserved.
PY - 2011
Y1 - 2011
N2 - Estimating the magnitude of past tsunamis after their deposits, including boulders, is one of the major issues to be developed in studies on tsunami hazard assessment. Hundreds of coral boulders have been transported from the fringing reef and some of them protruded to the land by the 2004 Indian Ocean tsunami at Lhok Nga bay, Sumatra, Indonesia. Eight coral boulders (axes lengths 3.1 m > a > 1.4 m, 2.5 m > b > 1.0 m and 1.8 m > hb > 0.6 m) whose density is about 1120 kg/m3 emplaced on the land are selected for numerical simulation. Results reveal that the coral boulders are transported both onshore and offshore directions by tsunami currents, and reproduce field observations within the error of ±40%. However, clast to clast interactions, surface micro-topographical effects and two dimensional current velocity effects are not considered in the numerical model. The onshore transport distance is higher than the offshore transport distance. No landward fining is observed in the field observations and the numerical simulation suggests that the offshore transport by backwash reworks the spatial distribution of boulders. The density of coral boulders affects greatly its transport distance.
AB - Estimating the magnitude of past tsunamis after their deposits, including boulders, is one of the major issues to be developed in studies on tsunami hazard assessment. Hundreds of coral boulders have been transported from the fringing reef and some of them protruded to the land by the 2004 Indian Ocean tsunami at Lhok Nga bay, Sumatra, Indonesia. Eight coral boulders (axes lengths 3.1 m > a > 1.4 m, 2.5 m > b > 1.0 m and 1.8 m > hb > 0.6 m) whose density is about 1120 kg/m3 emplaced on the land are selected for numerical simulation. Results reveal that the coral boulders are transported both onshore and offshore directions by tsunami currents, and reproduce field observations within the error of ±40%. However, clast to clast interactions, surface micro-topographical effects and two dimensional current velocity effects are not considered in the numerical model. The onshore transport distance is higher than the offshore transport distance. No landward fining is observed in the field observations and the numerical simulation suggests that the offshore transport by backwash reworks the spatial distribution of boulders. The density of coral boulders affects greatly its transport distance.
KW - Backwash
KW - Coral boulders
KW - Current velocity
KW - Landward fining
KW - Numerical simulation
KW - Tsunami
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M3 - Conference contribution
AN - SCOPUS:85066123567
T3 - 34th IAHR Congress 2011 - Balance and Uncertainty: Water in a Changing World, Incorporating the 33rd Hydrology and Water Resources Symposium and the 10th Conference on Hydraulics in Water Engineering
SP - 1294
EP - 1301
BT - 34th IAHR Congress 2011 - Balance and Uncertainty
PB - International Association for Hydro-Environment Engineering and Research (IAHR)
Y2 - 26 June 2011 through 1 July 2011
ER -