A computer-implemented method for generating an image of a subterranean formation based on pressure data that were continuously recorded during a geophysical survey, the method comprising: computing upgoing pressure wavefield data at stationary-receiver locations based on continuously recorded pressure data and vertical velocity data; computing a total source wavefield based on source wavefields emitted from individual airguns of a source; attenuating low-frequency noise in the upgoing pressure wavefield based on the total source wavefield to obtain low-frequency noise attenuated upgoing pressure wavefield data at stationary-receiver locations; and generating an image of the subterranean formation, or data indicative thereof, based at least in part on the low-frequency noise attenuated upgoing pressure wavefield data at stationary-receiver locations, thereby reducing low frequency noise artifacts in the image, wherein attenuating the low-frequency noise in the upgoing pressure wavefield to obtain the low-frequency noise attenuated upgoing pressure wavefield data at stationary-receiver locations comprises: for each trace of the upgoing pressure wavefield data at stationary-receiver locations, deconvolving the total source wavefield from the trace of upgoing pressure wavefield data to obtain an earth response to the total source wavefield; extracting low-frequency noise from the earth response; computing a low-frequency noise contribution to the trace of upgoing pressure wavefield data based on the extracted low-frequency noise and the total source wavefield; and subtracting the low-frequency noise contribution to the trace of upgoing pressure wavefield data from the trace of upgoing pressure wavefield data to obtain a trace of low-frequency noise attenuated upgoing pressure wavefield data. computing upgoing pressure wavefield data at stationary-receiver locations based on continuously recorded pressure data and vertical velocity data; computing a total source wavefield based on source wavefields emitted from individual airguns of a source; attenuating low-frequency noise in the upgoing pressure wavefield based on the total source wavefield to obtain low-frequency noise attenuated upgoing pressure wavefield data at stationary-receiver locations; and generating an image of the subterranean formation, or data indicative thereof, based at least in part on the low-frequency noise attenuated upgoing pressure wavefield data at stationary-receiver locations, thereby reducing low frequency noise artifacts in the image, wherein attenuating the low-frequency noise in the upgoing pressure wavefield to obtain the low-frequency noise attenuated upgoing pressure wavefield data at stationary-receiver locations comprises: for each trace of the upgoing pressure wavefield data at stationary-receiver locations, deconvolving the total source wavefield from the trace of upgoing pressure wavefield data to obtain an earth response to the total source wavefield; extracting low-frequency noise from the earth response; computing a low-frequency noise contribution to the trace of upgoing pressure wavefield data based on the extracted low-frequency noise and the total source wavefield; and subtracting the low-frequency noise contribution to the trace of upgoing pressure wavefield data from the trace of upgoing pressure wavefield data to obtain a trace of low-frequency noise attenuated upgoing pressure wavefield data. deconvolving the total source wavefield from the trace of upgoing pressure wavefield data to obtain an earth response to the total source wavefield; extracting low-frequency noise from the earth response; computing a low-frequency noise contribution to the trace of upgoing pressure wavefield data based on the extracted low-frequency noise and the total source wavefield; and subtracting the low-frequency noise contribution to the trace of upgoing pressure wavefield data from the trace of upgoing pressure wavefield data to obtain a trace of low-frequency noise attenuated upgoing pressure wavefield data.