Moraes, Marcio Augusto Ernesto deMendes Filho, Walter ManoelMendes, Rodolfo MoredaBortolozo, Cassiano AntonioMetodiev, DanielAndrade, Marcio Roberto Magalhães deEgas, Harideva MarturanoMendes, Tatiana Sussel GonçalvesPampuch, Luana Albertani2025-02-272025-02-27https://repositorio.univap.br/handle/123456789/600Landslides are highly dangerous phenomena that occur in different parts of the world and pose significant threats to human populations. Intense rainfall events are the main triggering process for landslides in urbanized slope regions, especially those considered high-risk areas. Various other factors contribute to the process; thus, it is essential to analyze the causes of such incidents in all possible ways. Soil moisture plays a critical role in the Earth’s surface-atmosphere interaction systems; hence, measurements and their estimations are crucial for understanding all processes involved in the water balance, especially those related to landslides. Soil moisture can be estimated from in-situ measurements using different sensors and techniques, satellite remote sensing, hydrological modeling, and indicators to index moisture conditions. Antecedent soil moisture can significantly impact runoff for the same rainfall event in a watershed. The Antecedent Precipitation Index (API) or “retained rainfall,” along with the antecedent moisture condition from the Natural Resources Conservation Service, is generally applied to estimate runoff in watersheds where data is limited or unavailable. This work aims to explore API in estimating soil moisture and establish thresholds based on landslide occurrences. The estimated soil moisture will be compared and calibrated using measurements obtained through multisensor capacitance probes installed in a high-risk area located in the mountainous region of Campos do Jordão municipality, São Paulo, Brazil. The API used in the calculation has been modified, where the recession coefficient depends on air temperature variability as well as the climatological mean temperature, which can be considered as losses in the water balance due to evapotranspiration. Once the API is calibrated, it will be used to extrapolate to the entire watershed and consequently estimate soil moisture. By utilizing recorded mass movements and comparing them with API and soil moisture, it will be possible to determine thresholds, thus enabling anticipation of landslide occurrences.PDFen-USArtigos de PeriódicosMarcio Augusto Ernesto de Moraes10.4236/ijg.2024.151006LandslidesAntecedent Precipitation IndexSoil MoistureThresholdWater BalanceMoraes, Marcio Augusto Ernesto de et al. Antecedent Precipitation Index to Estimate Soil Moisture and Correlate as a Triggering Process in the Occurrence of Landslides. International Journal of Geosciences, v. 15, n. 1, p. 70-86, 2024. Disponível em: https://www.scirp.org/journal/doi.aspx?doi=10.4236/ijg.2024.151006.Centro Nacional de Monitoramento e Alertas de Desastres NaturaisUniversidade Federal de GoiasUniversidade do Vale do ParaíbaUniversidade do Estado de São Paulo