Correlation between Rainfall and Mass Movements in North Coast Region of Sao Paulo State, Brazil for 2014-2018

Abstract

The monitoring of related hourly and accumulated rainfall index requires that critical thresholds of accumulated 72 hours rainfall are updated frequently according with the factors and local conditions (natural and anthropic) of each specific risk area. The importance of empirical methods is fundamental to confirm the relationship between rainfall intensity and accumulated rainfall with the mass movement events, in order to establish the critical threshold values. The present work performs an evaluation of the record data of mass movement events occurred in Sao Paulo State North coast region for a 4-year period (2014 to 2018) considering different mass movement characteristics (slope type, magnitude and impact level). Some rainfall values were obtained to show that within these parameters an event related to natural and anthropic features was triggered. A database was created, sorting source of information and municipalities monitored, to implement the correlation between the mass movement events and the rainfall values. To elaborate the event's map, reliable record data of localization of the mass movement events was selected, as well as the nearest possible raingauges of CEMADEN (National Center for Monitoring and Early Warning of Natural Disasters); also the exact event triggering time, selection by the slope type, the magnitude and the impact level of the mass movement event. The rainfall values of these raingauges allowed the calculation of the accumulated rainfall index for 1, 3, 6, 24, 48, 72 and 96 hours, with the adoption of the 72 hours index for this work. The correlation graphics are divided by the slope type, the magnitude and the impact level of the mass movement event. Different How to cite this paper: Metodiev, D.event by the influence level of triggering factors, natural and/or anthropic.

Landslides Triggered by the May 2017 Extreme Rainfall Event in the East Coast Northeast of Brazil

“…In the following days (29 and 30 May), there was a convection shift to the north of the ECNEB (Figure 9g,h), resulting in high rainfall in the State of Paraíba that caused a landslide on 29 May in João Pessoa (Table A1). This situation shows that the landslides can also be related to the accumulated rainfall from previous days, which influences the soil saturation processes [13,62]. At the beginning of the convective activity at the ECNEB, areas with vertical upward movement over the Atlantic Ocean (~9° S, 32° W; 11° S, 36° W) at 500 hPa were identified (Figure 11b).…”

“…The Brazilian Classification and Coding of Disasters groups potential threats to landslide incidents into four types: rockfall, topple, slides, and debris flows [9]. In the ECNEB, one of the main triggers of disasters is the erratic pattern of rainfall, where most events involving victims are related to landslides [10,11] Landslide events recorded across the country demonstrate the need to improve the ability to monitor, predict and issue landslide alerts in advance to minimize related damage and protect human lives and properties [12,13]. In this context, the ECNEB is predisposed to disasters associated with landslides due to geological and geomorphological factors as well as the disorganized land occupation [10,14].…”

Investigação da relação chuva-deslizamentos no município de Mauá – SP para obtenção de limiares críticos deflagradores de deslizamentos

“…Com base na metodologia de Tatizana et al (1987 a, b), utilizada por diferentes autores no estudo da relação entre a precipitação e deslizamentos isolados ou generalizados no território brasileiro (IDE; MACEDO, 2005;CASTRO et al, 2012;OLIVEIRA et al, 2016;METODIEV et al, 2018, entre outros), os dados de ocorrências de deslizamentos selecionados nesta etapa do trabalho foram associados à precipitação diária e à acumulada de chuvas em vários dias anteriores, sendo testados acumulados em diferentes períodos.…”

“…Vários autores, entre eles, Parizzi et al (2010), Castro et al (2012), Oliveira et al (2017) e Metodiev et al (2018), enfatizaram que, a precipitação acumulada em ambientes urbanos não foi, em muitos casos, o agente condicionante dos processos geodinâmicos e correlatos, sendo, porém, o agente deflagrador , devido a significativa interferência antrópica.…”

Sistemas Comunitários de Alerta de Risco de Desastres Associados a Inundações e Deslizamentos: Aspectos Teóricos e Metodológicos

“…Para desenvolvimento e aplicação do modelo de correlação entre índices pluviométricos e ocorrências de movimentos de massa baseado em Tatizana et al (1987) 3 , a organização de um próprio banco de dados pelas Defesas Civis é muito importante. As etapas de correlação envolvem uma sequência composta por Metodiev et al (2018): 3. Há ainda a metodologia desenvolvida pelo Projeto Gides, que atualmente se encontra em fase de testes.…”