https://www.sarahklassen.ca/home daily 1.0 2025-05-12 https://images.squarespace-cdn.com/content/v1/5d9e16cdce34672d69a34a9a/1570642794413-ZQ4SE8D97XFLBRC1T4RO/2017-11-19%2B17.02.15_edited%2Bcopy.jpg Home About Me I am an archaeologist deeply committed to unraveling the complex relationship between urbanism, rural agriculture, and sustainability in the face of shifting socio-environmental conditions. Through my interdisciplinary research, I aim to uncover how historical societies navigated these challenges, offering valuable insights for modern sustainable practices. https://images.squarespace-cdn.com/content/v1/5d9e16cdce34672d69a34a9a/1570651600945-1TWECGDV6G0FF9E6M8U4/2%2B-%2BCALI.jpg Home - Cambodian Archaeological Lidar Initiative https://images.squarespace-cdn.com/content/v1/5d9e16cdce34672d69a34a9a/1570652161184-9Q0CKYUXXGYMJB8D97JD/Dissertation2.jpg Home - Greater Angkor Project https://images.squarespace-cdn.com/content/v1/5d9e16cdce34672d69a34a9a/1570652204569-8V4IWRNRFTT8LTSE09M8/3%252B-%252BKALC.jpg Home - Khmer Archaeological Lidar Consortium https://images.squarespace-cdn.com/content/v1/5d9e16cdce34672d69a34a9a/1570651778888-QPF74LTGMCXLMM7UTJ6V/Klassen_Tiago_Phakdey.jpg Home - Koh Ker Archaeological Project https://images.squarespace-cdn.com/content/v1/5d9e16cdce34672d69a34a9a/1570642720921-YECA7OSATZ555EJKYZ6R/Dissertation1.jpg Home Dissertation 13.4125° N, 103.8670° E Angkor, Cambodia (9th-14th centuries C.E.) is home to one of the largest medieval water management systems in the world. How was the system constructed and how did it respond to climatic and social challenges? https://images.squarespace-cdn.com/content/v1/5d9e16cdce34672d69a34a9a/1622619351824-IJZW10XKUO8QBPHNFWQX/equinox.jpg Home - Chasing the Equinox https://images.squarespace-cdn.com/content/v1/5d9e16cdce34672d69a34a9a/faf1b34b-a522-4d05-bb00-08210967fbef/3.jpg Home - Lost Cities of the Jungle https://images.squarespace-cdn.com/content/v1/5d9e16cdce34672d69a34a9a/1622617310961-17CJ1PD7N7FDAY9V7127/IMG_6207.jpg Home - Ancient China from Above https://images.squarespace-cdn.com/content/v1/5d9e16cdce34672d69a34a9a/ff531542-4598-4e1b-b7ee-8a14e04e559d/Expedition+Unknown.JPG Home - Expedition Unknown https://images.squarespace-cdn.com/content/v1/5d9e16cdce34672d69a34a9a/66ed4f26-770a-4c30-9b75-9de47e42682e/Science_Advances.PNG Home Diachronic modeling of the population within the medieval Greater Angkor Region settlement complex https://images.squarespace-cdn.com/content/v1/5d9e16cdce34672d69a34a9a/bb7cec63-4789-4808-b26b-374b08a51f1d/Capture.PNG Home A metropolis arose in medieval Cambodia - new research shows how many people lived in the Angkor Empire over time https://images.squarespace-cdn.com/content/v1/5d9e16cdce34672d69a34a9a/1570733107482-2HIFK80ED8Z6CUDXV56C/plos.PNG Home Archaeologists often need to date and group artifact types to discern typologies, chronologies, and classifications. For over a century, statisticians have been using classification and clustering techniques to infer patterns in data that can be defined by algorithms. In the case of archaeology, linear regression algorithms are often used to chronologically date features and sites, and pattern recognition is used to develop typologies and classifications. However, archaeological data is often expensive to collect, and analyses are often limited by poor sample sizes and datasets. Here we show that recent advances in computation allow archaeologists to use machine learning based on much of the same statistical theory to address more complex problems using increased computing power and larger and incomplete datasets. This paper approaches the problem of predicting the chronology of archaeological sites through a case study of medieval temples in Angkor, Cambodia. For this study, we have a large dataset of temples with known architectural elements and artifacts; however, less than ten percent of the sample of temples have known dates, and much of the attribute data is incomplete. Our results suggest that the algorithms can predict dates for temples from 821–1150 CE with a 49-66-year average absolute error. We find that this method surpasses traditional supervised and unsupervised statistical approaches for under-specified portions of the dataset and is a promising new method for anthropological inquiry. https://images.squarespace-cdn.com/content/v1/5d9e16cdce34672d69a34a9a/1570733107020-67NJUK4MQM8TBFGFK67D/geo.PNG Home Ground penetrating radar, probing, and excavation were used to create a contour map of the topography of a buried laterite pavement forming the spillway of a large abandoned reservoir at the Angkorian‐period city of Koh Ker in Cambodia. Calculations of the flow velocity of water through the spillway, based on the topography of the laterite surface, demonstrate that this outlet was even less adequate for passing the flow of water from the Stung Rongea catchment than had been estimated previously by Lustig, Klassen, Evans, French, & Moffat (2018). We argue that this design flaw contributed substantially to the failure of the reservoir’s dike, possibly during the first rainy season after construction, which may have contributed to Koh Ker’s remarkably short‐lived tenure as the political center of the Khmer Empire. https://images.squarespace-cdn.com/content/v1/5d9e16cdce34672d69a34a9a/1570733107854-EL5FXC6V1IGDPPFLCSXI/JASR.PNG Home This paper examines the construction and design of a 7-km long embankment, probably built for King Jayavarman IV between 928 and 941 CE, as part of a new capital. We calculate that the capacities of the outlets were too small, and conclude that the embankment failed, probably within a decade of construction, so that the benefits of the reservoir stored by the embankment and the access road on top of it were lessened substantially. We explain how the design was sub-optimal for construction, and that while the layout had a high aesthetic impact, the processes for ensuring structural integrity were poor. Simple and inexpensive steps to secure the weir were not undertaken. We speculate that this early failure may have contributed to the decision to return the royal court and the capital of the Khmer Empire to the Angkor region, marking a critically important juncture in regional history. https://images.squarespace-cdn.com/content/v1/5d9e16cdce34672d69a34a9a/1570733107948-9L1WFKB82QSOIWKXB8RH/American.PNG Home Turquoise has played an important role in the Southwest, both today and in the distant past. Increasingly, archaeologists are coming to appreciate that the mineral was likely valued for its symbolism, rather than its chemical properties or economic worth. Thus, the color blue-green and a variety of blue-green things may have been conceptually analogous, together referencing and petitioning moisture. J. J. Brody recognized that additional symbols, while not themselves blue-green, may have likewise belonged to this blue-green complex. Over a decade ago, and while testing Brody’s hypothesis, Stephen Plog convincingly argued that black-on-white hachure in Gallup-Dogoszhi pottery served as a proxy for blue-green. Here, we ask whether Mimbres artists incorporated the same symbolism. Findings suggest that Mimbres hachure was likely representative of color but not necessarily blue-green. In fact, it may have referenced yellow. Yellow and blue are often paired among the Pueblos, and interregional differences in the meaning of hachure may relate to interregional complementarity. https://images.squarespace-cdn.com/content/v1/5d9e16cdce34672d69a34a9a/1573847097951-7XUVG4AIJUOVIU9NZWN7/Sapiens.PNG Home https://images.squarespace-cdn.com/content/v1/5d9e16cdce34672d69a34a9a/1587404759931-25TJ21BN6FHZ4G10D3SN/cohen.PNG Home Airborne laser scanning or lidar has now been used by archaeologists for twenty years, with many of the first applications relying on data acquired by public agencies seeking to establish baseline elevation maps, mainly in Europe and North America. More recently, several wide-area acquisitions have been designed and commissioned by archaeologists, the most extensive of which cover tropical forest environments in the Americas and Southeast Asia. In these regions, the ability of lidar to map microtopographic relief and reveal anthropogenic traces on the Earth’s surface, even beneath dense vegetation, has been welcomed by many as a transformational breakthrough in our field of research. Nevertheless, applications of the method have attracted a measure of criticism and controversy, and the impact and significance of lidar are still debated. Now that wide-area, high-density laser scanning is becoming a standard part of many archaeologists’ toolkits, it is an opportune moment to reflect on its position in contemporary archaeological practice and to move towards a code of ethics that is vital for scientific research. The papers in this Special Collection draw on experiences with using lidar in archaeological research programs, not only to highlight the new insights that derive from it but also to cast a critical eye on past practices and to assess what challenges and opportunities remain for developing codes of ethics. Using examples from a range of countries and environments, contributions revolve around three key themes: data management and access; the role of stakeholders; and public education. We draw on our collective experiences to propose a range of improvements in how we collect, use, and share lidar data, and we argue that as lidar acquisitions mature we are well positioned to produce ethical, impactful, and reproducible research using the technique. https://images.squarespace-cdn.com/content/v1/5d9e16cdce34672d69a34a9a/1587404960667-C5M1YKUEAVW4ND9M3YF7/Klassen.PNG Home The Greater Angkor region, in northwestern Cambodia, was home to several successive capitals of the Khmer Empire (9th to 15th centuries CE). During this time, the Khmer developed an extensive agricultural and water management system characterized by top-down state-sponsored hydraulic infrastructure. Archaeological evidence now shows that the well-documented state temples and water management features formed the core of an extended settlement complex consisting of many thousands of ponds, habitation mounds, and community temples. These community temples are difficult to date, and so far, the lack of chronological resolution in surface archaeological data has been the most significant challenge to understanding the trajectory of Angkor’s growth and decline. In this paper, we combine heterogeneous archaeological datasets and create diachronic models of the landscape as it was developed for agricultural production. We trace the foundation of new temple communities as they emerge on the landscape in relation to the construction of extensive state-sponsored hydraulic infrastructure. Together, these two forms of water management transformed over 1000 km2 of the Greater Angkor Region into an elaborate engineered landscape. Our results indicate that, over time, autonomous temple communities are replaced by large, state-sponsored agricultural units in an attempt by the state to centralize production. https://images.squarespace-cdn.com/content/v1/5d9e16cdce34672d69a34a9a/1609264486180-XIXII7BJRM8XDC6ZEOEM/Sapiens_Angkor.PNG Home Over a thousand years ago, the ancient Khmer civilization emerged as a powerful cultural and political force in what is now Cambodia and came to dominate much of Southeast Asia. Between the 9th and 15th centuries, the Khmer Empire created some of the most spectacular architecture in history, including one of the largest religious monuments in the world: Angkor Wat. This magnificent stone temple is one of the most famous archaeological sites in the world, visited by over 2.6 million tourists a year. A nearby temple, Ta Prohm, was featured in the movie Tomb Raider. https://images.squarespace-cdn.com/content/v1/5d9e16cdce34672d69a34a9a/b306a258-8530-4b2d-ae6d-e5be098aba32/GPR.PNG Home The Greater Angkor Region was the center of the Khmer Empire from the 9th until the 13th to the 14th centuries CE, when it entered a period of decline. Many studies have suggested that the decline of Angkor was precipitated by several factors, including severe monsoons, geopolitical shifts, and invasions. In this paper, we use light detection and ranging and ground penetrating radar to investigate the possible intersection of two of these existential threats in one feature: the North BankWall. Our results indicate that this feature was designed with dual functionality of extending the urban area’s defenses to the east of Angkor Thom while maintaining the existing infrastructure for the distribution and disposal of water. These findings suggest that the North Bank Wall was built before the severe droughts in the mid-13th century. The timing of the construction indicates that the perceived need for additional security—whether from internal factional disputes or external adversaries—predated the final adaptations to the hydraulic network during the unprecedented monsoon variability of the 14th century. These results indicate that perceived political unrest may have played a more important role in the decline of the site than previously known. https://images.squarespace-cdn.com/content/v1/5d9e16cdce34672d69a34a9a/f0a061bb-816a-45d4-95a7-d801b669287b/evolution.PNG Home The evolution of agro-urbanism: A case study from Angkor, Cambodia https://images.squarespace-cdn.com/content/v1/5d9e16cdce34672d69a34a9a/d98f9ad7-a574-44f9-8aa3-3c78a4a89b0c/JAMT.PNG Home https://images.squarespace-cdn.com/content/v1/5d9e16cdce34672d69a34a9a/3c31f044-6d26-4ae7-b5c0-ff50ac0fad2c/Bayes.JPG Home https://www.sarahklassen.ca/researchinterests daily 0.75 2020-12-29 https://www.sarahklassen.ca/researchprojects daily 0.75 2025-03-21 https://images.squarespace-cdn.com/content/v1/5d9e16cdce34672d69a34a9a/1570651542169-HCGTUHTRWD3LB565N5CV/2+-+CALI.png Research Projects https://images.squarespace-cdn.com/content/v1/5d9e16cdce34672d69a34a9a/1570735340013-N1W74OS1EHYEAEBGMDX3/koh+ker.jpg Research Projects https://images.squarespace-cdn.com/content/v1/5d9e16cdce34672d69a34a9a/1570651842462-KNLNVAEET6BPHKXLXQXB/3+-+KALC.png Research Projects https://images.squarespace-cdn.com/content/v1/5d9e16cdce34672d69a34a9a/1570652052061-NYOZIOZKWK4AOGUV8XCD/Dissertation2.jpg Research Projects https://www.sarahklassen.ca/dissertation daily 0.75 2020-12-29 https://www.sarahklassen.ca/cultural-resource-management daily 0.75 2024-12-20 https://www.sarahklassen.ca/take-action daily 0.75 2025-05-09