Surface Architectural Scanning of Archaeological Sites with Ground Based Lidar in Southern Peru Patrick Ryan Williams The Field Museum Chicago, Illinois USA rwilliams@fieldmuseum.org Ana Cristina Londoño Saint Louis University St. Louis, Missouri USA alondono@slu.edu Megan L. Hart University of Missouri Kansas City, Missouri USA hartme@umkc.edu Donna J. Nash University of North Carolina Greensboro, North Carolina USA djnash@uncg.edu Sofia Chacaltana C. Pontificia Universidad Católica del Perú Lima, Peru sofichacaltana@hotmail.com Megan L. Hente Saint Louis University St. Louis, Missouri USA mhente1@slu.edu Abstract— Ground based LiDAR scanning provides an innovative technique for investigating partially buried architectural structures in Southern Peru. In this paper, we evaluate the potential of ground-based LiDAR for elucidating the nature of archaeological structures with vestiges of architecture remaining on the surface. Microtopographic mapping provides evidence for subsurface architecture as well as documentation of elements of preserved standing constructions. We evaluate the potential for LiDAR to provide data on submerged structures as a complement to geophysical and excavation techniques. We also examine LiDAR’s role in documenting erosional processes and in enhancing monitoring of destruction to monumental archaeological sites. Two sites are examined as case studies: the Inka (1450-1532 CE) administrative center of Sabaya and the Wari (600-1000 CE) administrative center at Cerro Baúl. Keywords— archaeological prospection; archaeological mapping; laser scanning; Andean Prehistory I. INTRODUCTION Some of the most impressive and important of archaeological remains are the remnants of architectural constructions made by past civilizations. Ranging from landscapes [1] to modified caves [2,3], monumental palaces [4] to humble abodes [5,6], these constructions frame the context of human activities through the built environment. While certain well-preserved monuments capture the imagination of the public [7], the vast majority of human ingenuity in architectural construction remains obscured through the ravages of time. Vestiges of these great achievements of humankind remain preserved in the earth, yet to be documented and studied. While ground based laser scanning has been applied successfully to standing monuments [8,9,10], we utilize the method as an addition to a remote sensing toolset in the search for the structure of buried monuments and common houses. Subtle variations in surface topography can yield clues to subterranean buildings. Here we explore the role of ground- based LiDAR in archaeological sites in far southern Peru to assess the potential for architectural analysis of buried structures. II. PREVIOUS RESEARCH For the past 30 years, archaeological research in the Moquegua Valley of Southern Peru has documented hundreds of archaeological sites, including extensive excavations at dozens of monuments. Yet, only a small portion of the area’s buried architectural patrimony has been investigated systematically. Even sites with decades of extensive research, such as the monuments at Cerro Baul and Sabaya, have a great deal of information yet to be recovered. Previous research has involved surface architectural mapping with differential GPS and Total Station mapping [11, 12], geophysical investigations including magnetometry and ground penetrating radar [13], and wide area excavations aimed at defining architectural spaces [14]. These research agendas have been illuminating, but have not grasped the full potential of documentation. Surface mapping is dependent on identifying the vestiges of buried architecture with the naked eye. It is often imprecise due to the vagaries of preservation of architectural remains and the inability to identify architectural compounds based on fragments of surface remnants. Geophysical investigations have limits as well. Magnetometry proves difficult to interpret in areas of volcanic formation where architectural construction is composed of the same volcanic material as the surrounding matrix. GPR is limited in the rock littered cores of monumental sites, where rubble is the predominant surface matrix and the differentiation between constructed walls and fallen debris is difficult to ascertain. Extensive excavations are costly, time intensive, and limited in area exposure. 605