ABEM Terrameter SAS 1000 / SAS 4000
- 97 -
14.5
GRAD4L(X)8 + GRAD4S8: 4-CHANNEL MULTIPLE GRADIENT
ARRAY CVES WITH 4 ELECTRODE CABLES
This combination of protocol files is intended for multiple gradient array CVES roll-along
measurements, and has been found very useful for a variety of applications. It offers a
resolution superior to the commonly used Wenner array, and thanks to 4-channel measuring
the increased data density does not become costly in terms of increased time required in the
field. Note that it is important to select the protocol files in the correct order, starting with the
long layout (GRAD4L8) before selecting the protocol for short layout (GRAD4S8). It gives a
dense near-surface cover, and a slightly sparser measurement pattern at long electrode
spacings. GRAD4S8 is designed to supplement GRAD4L8 for the shortest electrode spacings
only. GRAD4LX8 is similar to GRAD4L8 but supplemented with expanding Wenner-
Schlumberger measurements for the longest electrode separations in order to improve the data
cover for the largest investigation depths.
Array
type
Protocol name Address
file
No
of
data
ORG
No
of
data UP
No
of
data
DWN
Total
data for
one
layout
14
Gradient
GRAD4L(X)8 LONG
512(608) 248(340) 248(340)
1080
GRAD4S8
SHORT 248
160
160
14
Total number of data points for a four-cable layout using the procedure described in this manual.
Figure 29. Data cover of GRAD4L8 and GRAD4S8 for roll-along with three full stations
(minimum electrode spacing 5 metres). Note that many data points fall on top of
each other in multiple gradient array pseudosection plots.
