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Numerical modeling of the 2006 Java tsunami earthquake
Hanifa N.R.a,b, Meilano I.a,b, Sagiya T.a, Kimata F.a, Abidin H.Z.b
a Research Center of Seismology, Volcanology and Disaster Mitigation, Graduate School of Environmental Studies, Nagoya University, Nagoya, 464-8601, Japan
b Geodesy Research Division, Institut Teknologi Bandung, Bandung, 40132, Indonesia
[vc_row][vc_column][vc_row_inner][vc_column_inner][vc_separator css=”.vc_custom_1624529070653{padding-top: 30px !important;padding-bottom: 30px !important;}”][/vc_column_inner][/vc_row_inner][vc_row_inner layout=”boxed”][vc_column_inner width=”3/4″ css=”.vc_custom_1624695412187{border-right-width: 1px !important;border-right-color: #dddddd !important;border-right-style: solid !important;border-radius: 1px !important;}”][vc_empty_space][megatron_heading title=”Abstract” size=”size-sm” text_align=”text-left”][vc_column_text]© World Scientific Publishing Company.A M7.8 occurred off the coast of Pangandaran, Central Java, Indonesia at15:24 (08:24 UTC) on 17 July 2006, and excited a deadly tsunami of average 3—8 m that inundated the southern coast of Java. This event is considered as a tsunami earthquake based on the fact that the earthquake generated a much larger tsunami than expected from its seismic waves, its unusual long rupture, and its source mechanism. We modeled the tsunami propagation by solving a non-linear shallow water equation. The initial condition of the co-seismic deformation was computed from Okada’s formula,23 using several different source parameters. We simulated the tsunami propagation with a finite-difference numerical model using a system of multiple grids with one and two minutes grid sizes. The best model parameters to reproduce the observed tsunami heights are seismic moment Mo= 1.7 x 1021 Nm, average slip D = 12 m, and rupture area S = 14,000(70x 200)km2, with the rigidity of 10 GPa. The computed tsunami heights are in fair agreement with the runup observations along the south coast of Java. However, the same fault model results in a southward displacement of about 25 mm at BAKO station in west Java, which is too large compared with the observed value of 4 mm. This discrepancy can be attributed to two effects. First, if the source process was accompanied by splay faulting, vertical displacement of the sea floorbecomes larger and caused massive tsunami. Another possibility is an effect of structural heterogeneity. The source region of the 2006 Java earthquake is near thetrench, and a very small rigidity (10GPa) is appropriate. For the calculation of a far-field static displacement at BAKO, however, we need to assume the same amount of seismic moment (1.7 x 1021 Nm) with a normal rigidity (30 GPa). Then, the average slip is reduced to 8 m and the calculated displacement matches the observation. This example demonstrates the importance of taking structural heterogeneity into account in modeling crustal deformation, and an easy way to dealwith a heterogeneous structure is implied. With this methodology, it is also possible to estimate rigidity of the source region by adjusting the slip amount so that the same seismic moment can reproduce both the tsunami data and far-field displacement data.[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Author keywords” size=”size-sm” text_align=”text-left”][vc_column_text][/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Indexed keywords” size=”size-sm” text_align=”text-left”][vc_column_text][/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Funding details” size=”size-sm” text_align=”text-left”][vc_column_text][/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”DOI” size=”size-sm” text_align=”text-left”][vc_column_text]https://doi.org/10.1142/9789812836182_0016[/vc_column_text][/vc_column_inner][vc_column_inner width=”1/4″][vc_column_text]Widget Plumx[/vc_column_text][/vc_column_inner][/vc_row_inner][/vc_column][/vc_row][vc_row][vc_column][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][/vc_column][/vc_row]