microseismic mapping is very similar geophysically to seismology. in earthquake seismology, seismometers scattered on or near the surface of the earth record s-waves and p-waves that are released during an earthquake event. this allows for motion along the fault plane to be estimated and its location in the earth's subsurface mapped. hydraulic fracturing, an increase in formation stress proportional to the net fracturing pressure, as well as an increase in pore pressure due to leakoff. tensile stresses are generated ahead of the fracture's tip, generating large amounts of shear stress. the increases in pore water pressure and in formation stress combine and affect weaknesses near the hydraulic fracture, like natural fractures, joints, and bedding planes.