Quaternary eruptive history and hazard-zone model at Nevado del Tolima and Cerro Machin volcanoes, Colombia

Thouret, Jean‐Claude; Cantagrel, Jean‐Marie; Robin, Claude; Murcia, Armando; Salinas, Rosalba; Cepeda, Héctor

doi:10.1016/0377-0273(94)00073-p

Cited by 35 publications

(43 citation statements)

References 8 publications

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“…Blocks reach diameters up to 1.5-4 m; 6 Ibagué fan, composed by volcaniclastic, fluvial and debris flow deposits. From Thouret and Laforge (1994), Thouret et al (1995);INGEOMINAS (2009) and own field studies this improved resolution. An evaluation of the accuracy of the DEM was performed using 36 selected differential GPS elevation measurements along the Combeima river ranging from 1089 to 1832 m asl.…”

Section: Study Areamentioning

confidence: 95%

“…The caldera of Nevado del Tolima opened the first time around 140000 years ago (Thouret et al 1995). Thereafter, Thouret et al (1995) distinguish six eruptive stages over the past 16000 years, the last of which occurred between 3600 and 1700 years BP. Stratigraphical findings indicate several lahars reaching as far as 70 km downstream.…”

Section: Study Areamentioning

confidence: 99%

“…They were probably triggered by volcano-glacier interactions. Minor eruptions with tephra falls and debris flows occurred in 1826, 1828, 1918, and 1943(Thouret et al 1995, all of which reached a low Volcano Explosivity Index (VEI) of 2 (Siebert et al The left side refers to the vulnerability and the right to the hazard. Vulnerability and hazard data are both standardized and combined generating a vulnerability and a hazard map.…”

Section: Study Areamentioning

confidence: 99%

“…The current period of relatively low activity lasts approximately 1700 years and exceeds the average time interval of around 1000 years between the eruptive stages mentioned above. With respect to lahars, the eruptive history and its geomorphological instability render Nevado del Tolima more hazardous than Nevado del Ruiz (Thouret et al 1995).…”

Section: Study Areamentioning

confidence: 99%

“…The provincial capital city Ibagué is within the reach of its potential lahars (Cepeda and Murcia 1988;Thouret et al 1995;Cantagrel et al 1995;Huggel et al 2007). Furthermore, rainfall-triggered floods and landslides notoriously affect the region.…”

Section: Introductionmentioning

confidence: 99%

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A risk analysis for floods and lahars: case study in the Cordillera Central of Colombia

Künzler

Huggel

Ramı́rez³

2012

Nat Hazards

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The glacier-covered Nevado del Tolima in the Colombian Cordillera Central is an active volcano with potential lahars that might be more hazardous than those on Nevado del Ruiz. Furthermore, rainfalltriggered floods and landslides notoriously and severely affect the region. For effective disaster prevention, a risk analysis is of primary importance. We present here a risk analysis methodology that is based on the assessment of lahar and rainfall-related flood hazard scenarios and different aspects of vulnerability. The methodology is applied for populated centres in the Combeima valley and the regional capital Ibagué (*500,000 inhabitants). Lahar scenarios of 0.5, 1, 5, and 15 million m3 volume are based on melting of 1, 2, 10, and 25 % of ice, firn and snow, respectively, due to volcanic activity and subsequent lahar formation. For flood modelling, design floods with a return period of 10 and 100 years were calculated. Vulnerability is assessed considering physical vulnerability, operationalized by market values of dwelling parcels and population density, whereas social vulnerability is expressed by the age structure of the population and poverty. Standardization of hazard and vulnerability allows for the integration into a risk equation, resulting in five-level risk maps, with additional quantitative estimate of damage. The probability of occurrence of lahars is low, but impacts would be disastrous, with about 20,000 people and more directly exposed to it. Floods are much more recurrent, but affected areas are generally smaller. High-risk zones in Ibaguéare found in urban areas close to the main river with high social vulnerability. The methodology has proven to be a suitable tool to provide a first overview of spatial distribution of risk which is considered by local and regional authorities for disaster risk reduction. The harmonization of technical-engineering risk analysis and approaches from social sciences into common reference concepts should be further developed. Abstract The glacier-covered Nevado del Tolima in the Colombian Cordillera Central is an active volcano with potential lahars that might be more hazardous than those on Nevado del Ruiz. Furthermore, rainfall-triggered floods and landslides notoriously and severely affect the region. For effective disaster prevention, a risk analysis is of primary importance. We present here a risk analysis methodology that is based on the assessment of lahar and rainfall-related flood hazard scenarios and different aspects of vulnerability. The methodology is applied for populated centres in the Combeima valley and the regional capital Ibagué (*500,000 inhabitants). Lahar scenarios of 0.5, 1, 5, and 15 million m 3 volume are based on melting of 1, 2, 10, and 25 % of ice, firn and snow, respectively, due to volcanic activity and subsequent lahar formation. For flood modelling, design floods with a return period of 10 and 100 years were calculated. Vulnerability is assessed considering physical vulnerability, operationalized by market values of dwellin...

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Section: Study Areamentioning

confidence: 95%

Section: Study Areamentioning

confidence: 99%

Section: Study Areamentioning

confidence: 99%

Section: Study Areamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A risk analysis for floods and lahars: case study in the Cordillera Central of Colombia

Künzler

Huggel

Ramı́rez³

2012

Nat Hazards

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The influence of climate change on recent peat accumulation patterns of Distichia muscoides cushion bogs in the high‐elevation tropical Andes of Colombia

2013

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[1] Extensive cushions of Distichia muscoides found at high elevations in the Andes form deep deposits of peat and function as peatland. The location of Distichia peatlands at the highest elevations makes them susceptible to the effects of global change including global warming. Accumulation rates of organic matter are the key function of peatland ecosystems and are highly susceptible to changes in climate. This study used Pb activity with depth indicated rapid accumulation in recent times. Organic matter had a mean accumulation rate of 1400 g m À2 yr À1 during the past 10 years, with values well above the observed regional accumulation rate of 300-400 g m À2 yr À1 . The same pattern was observed in peat accretion rates, with growth rates of 1-2 cm per year during the last 10 years. Cushion plants engineer their own environment, allowing the system to be less susceptible to direct changes in climate. However, the high rates of peat accretion in recent times may be originated from increasing temperatures and excess water from nearby glacier melt. However, glaciers are predicted to disappear during the next 20 years in the northern Andes, reducing water inputs in tropical high-elevation ecosystems.

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Transverse architecture of lahar terraces, inferred from radargrams: preliminary results from Semeru Volcano, Indonesia

Gomez

Lavigne

2010

Earth Surf Processes Landf

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Semeru Volcano is the highest mountain of Java (Indonesia), and a vulcanian explosion occurs every 15 minutes on average, since 1967. Thus a constantly renewed stock of material and the heavy monsoon rainfall [3700 mm yr −1 at 1500 m above sea level (a.s.l.)] provide a perfect setting for the study of lahars and their deposits. Hence, we examined the architecture of lahars' terraces 9·5 km from the summit in the Curah Lengkong Valley. We fi rst used ground penetrating radar (GPR) over vertical exposures of the lahars cut-bank terraces. This allowed us to better understand transversal radargrams across terraces, which are not visually accessible in the fi eld.Preliminary results from a single radargram are very instructive, since (1) they prove that the lateral architecture does not correspond to that observed from banks only; (2) we could observe the presence of lenses and stratigraphic discontinuities; (3) the setting of the various units can also help reconstruct deposition processes and the chronology of different units. In order to fi nalize these preliminary results, we however need to perform multiple GPR radargrams and provide a complete set of results. Copyright

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Quaternary eruptive history and hazard-zone model at Nevado del Tolima and Cerro Machin volcanoes, Colombia

Cited by 35 publications

References 8 publications

A risk analysis for floods and lahars: case study in the Cordillera Central of Colombia

A risk analysis for floods and lahars: case study in the Cordillera Central of Colombia

The influence of climate change on recent peat accumulation patterns of Distichia muscoides cushion bogs in the high‐elevation tropical Andes of Colombia

Transverse architecture of lahar terraces, inferred from radargrams: preliminary results from Semeru Volcano, Indonesia

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