Receivers on Land Streamer
A land streamer in MASW is a platform on which geophones are attached without spikes so that all of them can be moved as one unit, facilitating the
mobility of receiver array. A land streamer can increase survey speed by an order of magnitude.
A land streamer can be used in MASW surveys
because of strong nature of surface waves as
illustrated on the right. Two field records were
obtained at the same location by using two
different types of receiver array; one with
geophones planted with conventional spikes (left)
and another with geophones on conical plates
(right). Both field records (top) and
corresponding dispersion images (bottom) show
almost identical results, indicating geophones can
be used without spikes for MASW surveys.
A land streamer can be constructed by using
various types of materials and installation
mechanisms of geophones as illustrated below.
An added weight at the bottom of each geophone
is only to ensure the physical contact with ground
surface (not hanging in the air). Experiments
indicate the weight itself does not play any critical
role in the effectiveness of recording as far as a
minimum area of contact is maintained between
bottom of a geophone and ground surface.