{"id":2103,"date":"2026-10-28T20:57:46","date_gmt":"2026-10-28T20:57:46","guid":{"rendered":"https:\/\/colapso.ggf.br\/?p=2103"},"modified":"2026-10-28T20:57:47","modified_gmt":"2026-10-28T20:57:47","slug":"why-rainfall-alone-cannot-explain-landslide-disasters-in-salvador-brazil","status":"publish","type":"post","link":"https:\/\/colapso.ggf.br\/en\/why-rainfall-alone-cannot-explain-landslide-disasters-in-salvador-brazil\/","title":{"rendered":"Why Rainfall Alone Cannot Explain Landslide Disasters in Salvador, Brazil"},"content":{"rendered":"
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Research by the COLAPSO group links mass movements, infrastructure, and racial inequalities in Salvador, revealing the limits of risk management focused on emergency response.<\/strong><\/p>\n

During Salvador\u2019s rainy season, plastic sheeting stretched across hillsides is a familiar sight. Used as a temporary protective measure, these tarps also raise a question: what remains unresolved when an emergency covering becomes a lasting feature of the landscape? Understanding disasters in the city requires examining both the water entering the ground and the housing conditions, drainage systems, and public decisions that precede each event.<\/p>\n

This approach appears in a series of studies by Jilvana Ferreira da Silva Souza<\/strong>, supervised by Grace Bungenstab Alves<\/strong>, at the Federal University of Bahia (UFBA) within the COLAPSO research group. The research spans slope susceptibility, structural racism, and risk management, culminating in Souza\u2019s 2025 master\u2019s dissertation, Por tr\u00e1s da lona preta: necropol\u00edtica e deslizamentos em Salvador, Bahia<\/em>, and several conference publications.<\/p>\n

An initial analysis of institutional documents was published in 2023 under the same main title, Por tr\u00e1s da lona preta<\/em>. In 2024, the presentation \u201cCidade de papel: rela\u00e7\u00e3o entre precipita\u00e7\u00e3o e deslizamentos em Salvador, Bahia (Brasil)\u201d presented<\/em>\u00a0findings on rainfall and fatal events at the International Seminar on Multirisk.<\/p>\n

Terrain helps explain the process; the city helps explain the risk<\/h2>\n

Mass movements involve the downslope displacement of soil, rock, or other materials under gravity. The studies discussed here focus on landslides, a particular type of mass movement. Their occurrence depends on factors such as rock and soil properties, terrain characteristics, and water movement. Slope excavation, leaking pipes, and drainage changes can also compromise stability.<\/p>\n

A study by Jilvana Ferreira da Silva Souza, La\u00eds Fagundes Jesus Silva and Grace Bungenstab Alves, presented at the Brazilian Symposium on Applied Physical Geography in 2019, identified relationships between landslide occurrences, geological faults and boundaries between different rock types. The findings support an integrated approach to landscape analysis: slope steepness alone does not explain where events occur.<\/p>\n

Susceptibility and risk, however, describe different aspects of the problem. Susceptibility concerns a terrain\u2019s propensity for particular processes. Understanding risk and potential losses also requires considering the exposed people and buildings, their protection, and their capacity to cope with and recover from impacts.<\/p>\n

Research presented in Athens in 2019, involving Grace Bungenstab Alves and other team members, illustrated this distinction. Areas with high environmental susceptibility could have different levels of social vulnerability. In that analysis, these factors combined to increase risk in Salvador\u2019s northwestern part compared with the southeast.<\/p>\n

What fatality records reveal<\/h2>\n

In her 2025 dissertation, Souza examined records of mass movements and building collapses involving casualties between 2000 and 2015, alongside urban planning documents, public reports and rainfall data. The study assessed the two event types separately: a building collapse does not necessarily involve a mass movement on a slope.<\/p>\n

For the 38 deaths associated with landslides<\/strong> examined in the study, the final classification divided fatalities into three groups:<\/p>\n