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Usgs moment tens or s olution 2004 indian oc ean ear

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Unformatted text preview: the Nax is . USGS moment tens or s olution 2004 Indian Oc ean ear thquake To give an ex ample, in the 2004 Indian Oc ean earthquak e, the moment tens or s olution gives two nodal planes , one dipping northeas t at 13 degrees and one dipping s outhwes t at 79 degrees . In this c as e the earthquak e c an be c onfidently as s oc iated with the plane dipping s hallowly to the northeas t, as this is the orientation of the s ubduc ting s lab as defined by his toric al earthquak e loc ations and plate tec tonic models .[2] Fault plane s olutions are us eful for defining the s ty le of faulting in s eis mogenic volumes at depth for whic h no s urfac e ex pres s ion of the fault plane ex is ts , or where the fault trac e is c overed by an oc ean. A mos t beautifully s imple ex ample of a s uc c es s ful tes t of the hy pothes is of s ea floor s preading was the demons tration that the s ens e of motion along oc eanic trans form faults [3]is oppos ite to what would be ex pec ted in c las s ic al geologic interpretation of the offs et oc eanic ridges . This was done by c ons truc ting fault plane s olutions of earthquak es in oc eanic faults , whic h s howed beac h ball plots of s trik e s lip nature (s ee figures ), with one nodal plane parallel to the fault and the s lip in the direc tion required by the idea of s ea floor s preading from the ridges .[4] Fault plane s olutions als o play ed the k ey role in the dis c overy that the deep earthquak e z ones in s ome s ubduc ting s labs are under c ompres s ion, others are under tens ion.[5][6] Beach Ball Calculator [edit] There are s everal programs available to prepare Foc al Mec hanis m Solutions (FMS)[whi c h?]. BBC, a MATLAB bas ed tool box , is available to prepare the beac h ball diagrams . This s oftware plots the firs t motion polarity data arrived at different s tations . The c ompres s ion and dilation are s eparated us ing mous e help. A final diagram is prepared automatic ally .[7] en.wikipedia.or g /wiki/Focal_mechanism 3/3...
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This document was uploaded on 02/04/2014.

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