The Galperin source: A novel efficient multicomponent seismic source

Abstract

Multicomponent acquisition enables a more complete observation of the seismic wavefield compared with single-component measurements and has therefore experienced increased interest in the past few decades. Whereas the use of multicomponent receivers is well-established, efficient and effective multicomponent sources are still difficult to realize. One of the main drawbacks of common multicomponent sources is that the source coupling differs for different components. Differences in the source coupling can lead to amplitude variations introducing uncertainties when jointly analyzing data from two or three components (e.g., for multicomponent polarization analysis). To overcome this problem, we have designed a new multicomponent vector source, referred to as the Galperin source. The design is inspired by the Galperin receiver configuration, and it consists of three orthogonal source vectors ([Formula: see text], [Formula: see text], and [Formula: see text]), which all have the same inclination relative to the horizontal. Using the Galperin configuration, three orthogonal source components can be acquired without moving the source and changing the source coupling, which also increases acquisition efficiency. We built a prototype of the Galperin source and compared it with other multicomponent sources used for near-surface investigations. Comparisons in the time and frequency domains indicate a good agreement between data acquired using the Galperin source and other, more conventional, sources. However, because the three source acquisition vectors [Formula: see text], [Formula: see text], and [Formula: see text] and the resulting processing coordinates [Formula: see text], [Formula: see text], and [Formula: see text] are linked by a rotational matrix, errors on one component can project into others. Therefore, precise leveling of the Galperin source and identical source strength for all three source components is essential to minimize errors.