This document summarizes a technology for monitoring hydraulic fracturing operations using microseismic surface signals. It discusses how borehole monitoring is expensive but necessary to avoid losses, while surface monitoring has been difficult due to noise. The solution presented uses Optimal Statistical Algorithms (OSA) to suppress noise and extract signals, allowing useful information to be obtained from surface monitoring at a fraction of the cost of boreholes. The technology has been developed by Microseismic Inc. and attracted over $100 million in investments. It provides economic and monitoring benefits for evaluating fracture growth and mapping during hydraulic fracturing operations.