Skip to main content
USGS - science for a changing world

Geoelectric and Seismic Data acquired in the Precambrian Granite Gravel Aquifer, Llano Uplift, Central Texas, May 2017 - August 2018


Publication Date
Start Date
End Date


Ikard, S.J., Wallace, D.S., Teeple, A.P., Stanton, G.P., Merrill, K., and Pasley, N.K., 2019, Geoelectric and Seismic Data acquired in the Precambrian Granite Gravel Aquifer, Llano Uplift, Central Texas, May 2017 - August 2018: U.S. Geological Survey data release,


This data release contains geophysical data and well and borehole driller's logs acquired at a small field site in the Llano Uplift of central Texas. The field site is underlain by the unconfined Precambrian Granite Gravel aquifer and the Precambrian Town Mountain Granite bedrock from which the Granite Gravel Aquifer was derived through chemical and mechanical weathering. The data set consists of five types of data in the quantities indicated: (1) 1 time-domain electromagnetic sounding, (2) 441 self-potential measurements, (3) 2 electrical resistivity tomography profiles, (4) 2 seismic refraction tomography profiles, and (5) 4 driller's logs (obtained from 2 wells and 2 shallow boreholes). The data were collected primarily from within [...]


Attached Files

Click on title to download individual files attached to this item.

Main Figure.jpg thumbnail 184.93 KB
GGA_TDEM_100m_Input_20190619.usf 5.8 KB
GGA_TDEM_100m_Model_20190619.IXP 29.45 KB
GGA_TDEM_100m_Output_20190619.TXT 12.33 KB
GGA_SP_CR_Survey_Data.txt 39.19 KB
GGA_SP_Drift_Data.txt 73.71 KB
GGA_ERT_XYZ.txt 4.99 KB
GGA_Profile_ERT1_RES2D_Input_20190619.Dat 15.73 KB
GGA_Profile_ERT1_RES2D_Output_20190619.dat 14.85 KB
GGA_Profile_ERT2_RES2D_Input_20190619.Dat 15.73 KB
GGA_Profile_ERT2_RES2D_Output_20190619.dat 14.85 KB
GGA_RES2D_Inversion_Parameters_20190619.ivp 6.59 KB
GGA_SRT_Raw_Data.txt 9.21 MB
GGA_SRT_Survey_Geometry.txt 2.65 KB
GGA_SRT1_First_Arrivals.txt 2.96 KB
GGA_SRT1_Velocity_Model_Output.txt 7.43 KB
GGA_SRT2_First_Arrivals.txt 2.37 KB
GGA_SRT2_Velocity_Model_Output.txt 7.57 KB
GGA_Borehole_C_Drillers_Log.pdf 51.53 KB
GGA_Borehole_D_Drillers_Log.txt 691 Bytes
GGA_Well_A_Drillers_Log.pdf 53.11 KB
GGA_Well_B_Drillers_Log.pdf 52.65 KB
Original FGDC Metadata

86.29 KB
Well_A_Hydrograph_May_2017.txt 476 Bytes


Non-invasive geophysical methods (time-domain electromagnetic sounding, self-potential mapping, electric resistivity tomography, and seismic refraction tomography) were used with information obtained from driller's logs from two wells and two boreholes to create the dataset documented herein. These data were used in a companion journal article to help characterize the geophysical properties of the Precambrian Granite Gravel Aquifer and the Precambrian Town Mountain Granite in the Llano Uplift of central Texas. Because the objective was to achieve higher-resolution data than typical geophysical reconnaissance surveys provide, most of the data were collected within a 100-m by 100-m field site. One profile of seismic refraction data was also acquired outside of this area, centered upon an pre-existing well.

Additional Information


Type Scheme Key
DOI doi:10.5066/F72Z14G6

Item Actions

View Item as ...

Save Item as ...

View Item...