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7.1.11 Location by grid search

Hypocenter can also locate an event by grid search. This can be quite time consuming but illustrates well the problem with local minima. Grid search can only be done for one event at a time using EEV command 'grid'.

Hypocenter is started up and will ask for the grid: Latitude and longitude range and grid spacing. A maximum of 71 points can be used in each direction. The point with the lowest RMS is found and the corresponding location and residual is printed on the screen. It is now optionally possible to plot the contours on the screen. The map coordinates used are as de ned in SEISAN.DEF. Note that the grid search is using exactly the same parameters as Hypocenter. This includes all weights and phase types. The depth is xed to the depth given in the S- le header line. For more details and an example, see application note epi.pdf in INF.


next up previous contents index
Next: 7.1.12 Using HYP to Up: 7.1 The hypocenter program, Previous: 7.1.10 Alternative model   Contents   Index
Peter Voss : Tue Mar 27 13:05:57 UTC 2018