Imperfections like pores occurring due to high process dynamics during laser deep penetration welding reduce the weld quality and the strength of welded joints. It is assumed that keyhole instabilities are responsible for the high process dynamics. In order to better understand the correlation between pore formation and keyhole dynamics an analytical process model has been developed describing keyhole radius fluctuations in different depths depending on the process parameters. Modelled radius oscillation frequencies have been compared to experimentally measured process emissions. Frequency spectrums of acoustic process emission observations show similar tendencies of keyhole dynamics compared to the calculations. For pore detection x-ray photography has been used while pore percentage and pore number in the weld seams have been evaluated. The pore formation in the solidified weld seam is compared to the observed dynamic characteristics during the process. Higher keyhole frequencies tend to correlate with increased pore numbers at reduced pore sizes.