Preliminary Geological Investigation of Mission Nuestra Señora de la Purísima Concepción de Acuña for San Antonio Missions National Historical Park & World Heritage Site

A preliminary geological investigation of Mission Nuestra Señora de la Purísima Concepción de Acuña, part of the San Antonio Missions National Historical Park and UNESCO World Heritage Site, reveals ongoing subsidence of its limestone foundation. This subsidence has led to structural issues such as wall cracking, dissolution of the foundation's exterior, and the past appearance of a sinkhole adjacent to the building. The study employed ground-penetrating radar to detect changes in the bedrock beneath the compound and high-resolution coordinate and elevation data to monitor future subsidence. Chemical analysis of rainwater runoff from the church’s roof was conducted to assess its role in foundation dissolution. Comparisons between topographic profiles derived from county-wide lidar datasets and independently gathered data identified areas potentially requiring future maintenance. These findings highlight the need for continued monitoring and intervention to preserve this historic structure.

Quintero, E., & Mitchell, E. (2022). PRELIMINARY GEOLOGICAL INVESTIGATION OF MISSION NUESTRA SEÑORA DE LA PURÍSIMA CONCEPCIÓN DE ACUÑA FOR SAN ANTONIO MISSIONS NATIONAL HISTORICAL PARK & WORLD HERITAGE SITE. Geological Society of America Abstracts with Programs. https://doi.org/10.1130/abs/2022am-382591