Pore-fluid migration and the timing of the 2005 M8.7 Nias earthquake

K.L.H. Hughes; Timothy Masterlark; Walter D. Mooney

doi:10.1130/l109.1

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Pore-fluid migration and the timing of the 2005 M8.7 Nias earthquake

K.L.H. Hughes·Timothy Masterlark·Walter D. Mooney

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Abstract

Two great earthquakes have occurred recently along the Sunda Trench, the 2004 M9.2 Sumatra-Andaman earthquake and the 2005 M8.7 Nias earthquake. These earthquakes ruptured over 1600 km of adjacent crust within 3 mo of each other. We quantitatively present poroelastic deformation analyses suggesting that postseismic fluid flow and recovery induced by the Sumatra-Andaman earthquake advanced the timing of the Nias earthquake. Simple back-slip simulations indicate that the megapascal (MPa)–scale pore-pressure recovery is equivalent to 7 yr of interseismic Coulomb stress accumulation near the Nias earthquake hypocenter, implying that pore-pressure recovery of the Sumatra-Andaman earthquake advanced the timing of the Nias earthquake by ∼7 yr. That is, in the absence of postseismic pore-pressure recovery, we predict that the Nias earthquake would have occurred in 2011 instead of 2005.

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K.L.H. Hughes, Timothy Masterlark, Walter D. Mooney. 2011. Pore-fluid migration and the timing of the 2005 M8.7 Nias earthquake. https://doi.org/10.1130/l109.1

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