Surface penetrating radar investigation of adobe walls

Carlo Citto of ANA conducting radar scanning at Tumacácori with field support from NPS staff.

Atkinson-Noland & Associates, in collaboration with the National Park Service and the School of Engineering at the University of Vermont, recently completed a comprehensive investigation of the adobe walls at the Mission Church of San Jose de Tumacácori in Tumacácori National Historical Park using Surface Penetrating Radar (SPR). Dating back to the early 19th century, the Mission is built primarily of adobe with vaults and domes of clay bricks. Over the years, moisture penetration threatened both the structural integrity of the church and the historic frescos on the interior of the dome. In addition, an 1887 earthquake had caused significant damage to the adobe walls. The radar investigation is part of a seismic assessment of the Church that the team is conducting to identify structural deficiencies and recommend retrofit options. Surface penetrating radar was used extensively to evaluate the solidity of the adobe walls and inform the seismic analysis by providing three-dimensional mapping of voids within the walls.