Abstract: Disclosed is a method for determining skew measurements for clock errors in an autonomous seismic node. A parabolic fit may be used to estimate the clock drift of an ocean bottom seismic node during node deployment. A temperature and/or frequency trend and a real-time temperature measurement may be used to compute a temperature corrected parabolic trend. The temperature and/or frequency trend may be measured in a laboratory on a node by node basis or it may be a single trend that is suitable for all nodes. The method may include measuring clock skew prior to node deployment and after node recovery, correcting the pre and post deployment skew measurements based on a temperature and/or frequency trend and/or to a constant reference temperature, and/or computing a parabolic trend of the skew measurements of the clock based on the temperature corrected pre and post deployment skew measurements.

Abstract: A swath of marine seismic data is acquired using a plurality of receiver lines, at least two near sources and at least one far source. Lines of data corresponding to the far seismic source are augmented to produce additional lines of interpolated and/or extrapolated seismic data that are equivalent to that which would be produced by a second far source. This makes it possible to obtain fill coverage seismic data with a shorter cable length and also increases the acquisition speed relative to an acquisition method using two near and two far seismic sources.