Method and system for recording seismic signals

A method of recording seismic signals, comprising the steps of:

• providing a first array of non-vertically directed first borehole sections in an earth formation beneath an earth surface, comprising at least a first non-vertically directed first borehole section and a second non-vertically directed first borehole section;
• providing a second array of non-vertically directed second borehole sections in said earth formation, comprising at least a first non-vertically directed second borehole section;
• providing a first stationary seismic receiver array in the first non-vertically directed first borehole section, comprising at least one first stationary seismic receiver in a first receiver location, and providing a second stationary seismic receiver array in the second non-vertically directed first borehole section comprising at least one second stationary seismic receiver in a second receiver location;
• providing a seismic source assembly comprising a repeatable seismic source;
• moving the seismic source assembly axially through the first non-vertically directed second borehole section from at least a first position to a second position of a plurality of first borehole positions along a length of the first non-vertically directed second borehole section;
• activating the repeatable seismic source when the seismic source assembly is in the first position and recording a first shot of seismic signals with at least each of the first and second stationary seismic receivers;
• and
• activating the repeatable seismic source when the seismic source assembly is in the second position and recording a second shot of seismic signals with at least each of the first and second stationary seismic receivers;
• wherein activating the repeatable seismic source causes seismic waves to propagate through the earth formation and wherein each of the first and second stationary seismic receivers is sensitive to vertically propagating seismic waves and wherein the first and second shots of seismic signals are measured representations of said seismic waves interacting with the first and second stationary seismic receivers.