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We present a comprehensive set of observations of the interaction of p-modeoscillations with sunspots using surface-focused seismic holography. Maps oftravel-time shifts, relative to quiet-Sun travel times, are shown for incomingand outgoing p modes as well as their mean and difference. We compare resultsusing phase-speed filters with results obtained with filters that isolatesingle p-mode ridges, and further divide the data into multiple temporalfrequency bandpasses. The f mode is removed from the data. The variations ofthe resulting travel-time shifts with magnetic-field strength and with thefilter parameters are explored. We find that spatial averages of these shiftswithin sunspot umbrae, penumbrae, and surrounding plage often show strongfrequency variations at fixed phase speed. In addition, we find that positivevalues of the mean and difference travel-time shifts appear exclusively inwaves observed with phase-speed filters that are dominated by power in thelow-frequency wing of the p1 ridge. We assess the ratio of incoming to outgoingp-mode power using the ridge filters and compare surface-focused holographymeasurements with the results of earlier published p-mode scatteringmeasurements using Fourier-Hankel decomposition.

Surface-focused Seismic Holography of Sunspots: I. Observations