Yao, Z. S.Quintero, RonnieRoberts, R. G.2026-05-252026-05-251999https://hdl.handle.net/11056/3465445287 P-wave and 26813 S-wave arrival times from the data base of the Costa Rica network have been tomographically inverted to image the structure beneath Costa Rica. A regularized recursive least squares inverse method was used to produce the high resolution and minimum variance model parameter estimates. The first arrival times are calculated using a finite difference technique, which allows for flexible parameterization of the velocity model and easy inclusion of topography and source-receiver geometry. The P wave velocity structure and hypocenters are determined simultaneously, while the S wave velocity structure is determined using the relocated seismicity and an initial model derived from the P wave model assuming an average P to S wave velocity ratio of 1.78. The most prominent features in the inverted model are a low velocity structure under the volcanic chain in the center of the country, which is related to the hot material connected with the active volcanoes; and a high velocity zone in the mantle, which is related to the Cocos plate subducted under Costa Rica.engAttribution-ShareAlike 4.0 Internationalhttp://creativecommons.org/licenses/by-sa/4.0/COSTA RICATOMOGRAPHYTOMOGRAFIATOPOGRAPHYTOPOGRAFIAGEOMETRYGEOMETRIAhttp://purl.org/coar/resource_type/c_6501