The tailings dam failure of 5 November 2015 in SE Brazil and its preceding seismic sequence

Agurto‐Detzel, Hans; Bianchi, Marcelo; Assumpção, M.; Schimmel, Martin; Collaço, Bruno; Ciardelli, Caio; Barbosa, José Roberto; Calhau, Jackson

doi:10.1002/2016gl069257

Cited by 67 publications

(25 citation statements)

References 25 publications

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“…Three events were detected ~1.5 h prior to the dam collapse, presenting regional Richter magnitudes (mR) of between 1.4 and 2.6. Another small event was detected around the time of the accident; four more with mRs ranging between 1.3 and 1.9 occurred over the following days [5]. The events are consistent with seismic intensities IV-V in the Modified Mercalli intensity scale (MM), suggesting occurences at very shallow depths (<5 km).…”

Section: Introductionsupporting

confidence: 66%

Monitoring the Vulnerability of the Dam and Dikes in Germano Iron Mining Area after the Collapse of the Tailings Dam of Fundão (Mariana-MG, Brazil) Using DInSAR Techniques with TerraSAR-X Data

et al. 2018

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The Fundão tailings dam in the Germano iron mining complex (Mariana, Brazil) collapsed on the afternoon of 5 November 2015, and around 32.6 million cubic meters of mining waste spilled from the dam, causing polluion with mining waste along a trajectory of 668 km, extending to the Atlantic Ocean. The Sela & Tulipa and Selinha dikes, and the main Germano tailings dam, were directly or indirectly affected by the accident. This work presents an investigation using Advanced-Differential Interferometric Synthetic Aperture Radar (A-DInSAR) techniques for risk assessment in these critical structures during 18 months after the catastrophic event. The approach was based on the integration of SBAS (Small Baseline Subset) and PSI (Persistent Scatterer Interferometry) techniques, aiming at detecting linear and nonlinear ground displacements in these mining structures. It used a set of 48 TerraSAR-X images acquired on ascending mode from 11 November 2015 to 15 May 2017. The results provided by the A-DInSAR analysis indicated an overall stability in the dikes and in the main wall of Germano tailings dam, which is in agreement with in situ topographic monitoring. In addition, it was possible to detect areas within the reservoir showing accumulated values of up to −125 mm of subsidence, probably caused by settlements of the waste dry material due to the interruption of the mining waste deposition, and values up to −80 mm on auxiliary dikes, probably caused by continuous traffic of heavy equipment. The spatiotemporal information of surface displacement of this large mining structure can be used for future operational planning and risk control.

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Section: Introductionsupporting

confidence: 66%

Monitoring the Vulnerability of the Dam and Dikes in Germano Iron Mining Area after the Collapse of the Tailings Dam of Fundão (Mariana-MG, Brazil) Using DInSAR Techniques with TerraSAR-X Data

et al. 2018

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“…Large-scale submarine liquefaction may cause coastal areas to slip below sea level (as at Port Royal in 1692) [36] and result in large-scale coastal geomorphic reorganization. Even in recent times and in areas with a relatively small perceived seismic hazard, tailings dams may liquefy, resulting in catastrophic failure [37] [15,32-42]…”

Section: Liquefactionmentioning

confidence: 99%

Effects of Earthquakes on Flood Hazards: A Case Study From Christchurch, New Zealand

Quigley

Duffy

2020

Geosciences

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Earthquakes can influence flood hazards by altering the flux, volumes, and distributions of surface and/or subsurface waters and causing physical changes to natural and engineered environments (e.g., elevation, topographic relief, permeability) that affect surface and subsurface hydrologic regimes. This paper analyzes how earthquakes increased flood hazards in Christchurch, New Zealand, using empirical observations and seismological data. Between 4 September 2010 and 4 December 2017, this region hosted one moment magnitude (Mw) 7.1 earthquake, 3 earthquakes with Mw ≥ 6, and 31 earthquakes with local magnitude (ML) ≥ 5. Flooding related to liquefaction-induced groundwater pore-water fluid pressure perturbations and groundwater expulsion occurred in at least six earthquakes. Flooding related to shaking-induced ground deformations (e.g., subsidence) occurred in at least four earthquakes. Flooding related to tectonic deformations of the land surface (fault surface rupture and/or folding) occurred in at least two earthquakes. At least eight earthquakes caused damage to surface (e.g., buildings, bridges, roads) and subsurface (e.g., pipelines) infrastructure in areas of liquefaction and/or flooding. Severe liquefaction and associated groundwater-expulsion flooding in vulnerable sediments occurred at peak ground accelerations as low as 0.15 to 0.18 g (proportion of gravity). Expected return times of liquefaction-induced flooding in vulnerable sediments were estimated to be 100 to 500 years using the Christchurch seismic hazard curve, which is consistent with emerging evidence from paleo-liquefaction studies. Liquefaction-induced subsidence of 100 to 250 mm was estimated for 100-year peak ground acceleration return periods in parts of Christchurch.

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“…This incident is considered to be one of the largest environmental disasters in recent years (de Oliveira Neves et al 2016). Recent results indicate that the failure of the dam wall may have been triggered by a sequence of small-magnitude earthquakes (Agurto-Detzel et al 2016). This could suggest that the dam wall was in an already weakened state at this time, as the largest seismic event in this sequence had a relatively small moment magnitude of Mw = 2.6.…”

Section: Massive Dams Massive Risksmentioning

confidence: 99%

Imaging and monitoring tailings dam walls with ambient seismic noise

Wit¹,

Olivier²

2018

Proceedings of the 21st International Seminar on Paste and Thickened Tailings

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Tailings dams are massive structures that are designed to contain the waste slurry remaining after processing ore at open pit and underground mines. These structures fail far more regularly than normal water storage dams, and in recent years catastrophic tailings dam failures have occurred, causing significant damage to the environment and even loss of life. To mitigate these catastrophic events in the future, there is an urgent need to develop cost-effective methods to monitor the structural stability of these constructions over time. The lack of current cost-effective subsurface imaging and monitoring methods prompted us to investigate whether ambient seismic noise can be used to image and detect internal changes in a tailings dam wall during a period of heavy rainfall. We recorded three weeks of continuous seismic data with 10 short-period geophones at a tailings dam in Tasmania, Australia. Seismic interferometry was used on ambient noise to create virtual seismic sources. With these virtual source signals, small changes in seismic velocity were measured daily and compared to rainfall, seepage flow rates and fluid pore pressure. The observed velocity changes were driven by fluid saturation, groundwater level, increased loading from increased dam water level and a sudden increase in fluid pore pressure in a section of the dam wall. A further experiment was performed at a tailings dam in South Africa, where ambient noise surface wave tomography was used to image an area where seepage was identified. The results suggest that these relatively inexpensive methods can be used to monitor and locate small changes in the interior of tailings dam walls, providing a valuable tool for remotely monitoring the structural stability of tailings dam walls over time.

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The tailings dam failure of 5 November 2015 in SE Brazil and its preceding seismic sequence

Cited by 67 publications

References 25 publications

Monitoring the Vulnerability of the Dam and Dikes in Germano Iron Mining Area after the Collapse of the Tailings Dam of Fundão (Mariana-MG, Brazil) Using DInSAR Techniques with TerraSAR-X Data

Monitoring the Vulnerability of the Dam and Dikes in Germano Iron Mining Area after the Collapse of the Tailings Dam of Fundão (Mariana-MG, Brazil) Using DInSAR Techniques with TerraSAR-X Data

Effects of Earthquakes on Flood Hazards: A Case Study From Christchurch, New Zealand

Imaging and monitoring tailings dam walls with ambient seismic noise

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