ALMA-J Site Testing
＞ALMA-J Site Testing Archive	Last update 2005-02-04

Boring

Geotechnical study of six locations in the Chajnantor science preserve area was carried out in 2000 February as a joint work of NRO and NRAO. Location of the boreholes was carefully selected so that the study is useful both for selection of the ASTE/ALMA/LMSA sites and also for the design of their antenna foundation. The examined sites include a possible ASTE site, three potential ALMA compact configuration locations -- Pampa la Bola, Chajnantor South, and Chajnantor North -- and two locations along a possible locus of the ALMA 10 km configuration -- Chascon-Chajnantor saddle point and northeastern foot of Chascon. Each borehole was 15 m deep. But for the Chascon-Chajnantor saddle point, where we could easily dig a 160 cm deep hole, the subsurface conditions were found to be very promissing for the design of the antenna basement.

References

• Yashima, A., Zhang, F., Shigematsu, H., Endo, A., Nishida, K., & Sakamoto, S. 2001, "Geological and geotechnical study of ALMA site foundation in the Cerro Chascon science preserve,'' PNAOJ, 6, 65-74
• Rojas, L. 2000, "Geotechnical study, Chahnantor site, II Region," LMSA Memo 2000-004 (also ALMA Memo 408)

Photographs

• Core sample: Pampa la Bola, Chajnantor South, Chajnantor North, Saddle point, Chascon East