NH
Natural Hazards

Archives / 2018 / April

Permafrost fever, do we need a doctor?

Permafrost fever, do we need a doctor?

Today we will shed some light on permafrost thanks to Dr. Dmitry (Dima) StreletskiyDima is an Assistant Professor of Geography and International Affairs at the George Washington University. He leads several research grants focusing on various aspects of climate change and its impacts on natural and human systems in the Arctic. Streletskiy is the President Elect of the United Sates Permafrost Association and the Chair of Global Terrestrial Network for Permafrost.

If you want to see some videos on the topic, feel free to check the following links:

Video on youtube from Siberia field class on permafrost and urban sustainability: https://youtu.be/ZlblSd4g4gE

Video on youtube from Alaska field work https://www.youtube.com/watch?v=LqYcOiCQOGk

Dima has also agreed on sharing some pictures collected during his research. So, if you are curious, just scroll to the bottom of the interview and enjoy the view!

 

Hello Dima, could you please briefly define what permafrost is for our audience?

Permafrost plays an important role in global climate change, functioning of arctic ecosystems, and human activities in the cold regions. Permafrost is soil, rock, and any other subsurface earth material that exists at or below 0°C throughout at least two consecutive years, usually for decades up to millennia. Permafrost stands for perennially frozen ground (“existing more than two years”), not permanently frozen.  I think that this is one of the major popular misconceptions about permafrost. Permafrost is not permanent and is a rather dynamic phenomenon, which makes it increasingly relevant in the context of natural hazards. Even more dynamic, is the active layer, the layer overlying the permafrost, which thaws during the summer and refreezes the following winter affecting many biological and hydrological processes in permafrost regions.

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Steaming badly: what do we know about hazardous and less known hydrothermal eruptions in volcanic environments?

Photo 1. Yellowstone National Park. The Grand Prismatic Spring is the largest hot spring in the United States, and the third largest in the world. Photo credit: David Mencin (distributed via imaggeo.egu.eu)

Volcanic eruptions are among the fascinating natural phenomena we can observe on Earth. Along with being very attractive, they are hazardous for both society and infrastructures. Eruptive styles are various and today we focus our attention on one particular type of explosive event: hydrothermal eruptions. We have interviewed Cristian Montanaro on the topic.

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Multi-Natural-Hazards: how can we deal with such complex chain of events?

Multi-Natural-Hazards: how can we deal with such complex chain of events?

Today we have the honor to have Prof. Victor Jetten as our guest. Throughout his career Victor, has been working in modelling of natural hazard and land degradation processes. Starting with biomass and grazing capacity, the effects of logging on the natural rain forest water balance, he then moved to soil erosion and land degradation processes as a result of land use change and overgrazing. He believes that all these processes should not be studied and modeled as separate disciplines but in a much more holistic way. In the context of Natural Disasters stakeholders are confronted with chains of multiple hazards: such an earthquake leading to landslides leading to blockage of river systems leading to flash floods (such as happened in Wenchuan in 2008 and Nepal in 2016). Each subsequent extreme rainfall triggers landslides and extreme erosion, forging possibly more change in these areas than several decades of climate change, and wiping out years of development. Victor thinks science has to be useful for society and his aim is to provide timely and actionable spatial information in disaster preparedness, prevention and response. To this end he develops together with PhD researchers the opensource model openLISEM, that is able to simulate runoff, river discharge, floods, erosion and deposition and debris flows, in an integrated and spatially detailed way.

 

  1. Today we are going to talk about multi-hydromorphic-hazards. Victor, what can you tell us about it?

We have moved from theory and models to understand processes in nature to the application of that knowledge in a hazards context (as a result of triggers such as extreme weather events or earthquakes). The probability of that event was added, to serve stakeholders better. But things become complicated very rapidly: we almost never know the probability of the event itself, so we exchanged that for the probability of the driving process, which is not the same. Hazards happen at the same time or as a chain of events: the 2008 earthquake in Wenchuan had direct earthquake damage, triggered over 100000 landslides, hundreds of which dammed rivers that potentially led to flash floods. Flash floods are triggered after an el Nino year because the sparse vegetation led to overgrazing. This complexity gives us problems: we have different models for different processes made by separate groups of scientists: geomorphologists look at landslides, hydrologists at flooding (but not so much at sediment in floods and where sediment comes from), erosion is the domain of soil scientists and agriculture (but floods are far downstream), meteorologists focus on the weather part of hazards. This is perfectly natural as each of these are sciences in itself. But now you live on a Caribbean island and are hit by a hurricane. Your house is subject to sea surges, wind damage, flash floods and landslides. These effects are aggravated because of a lack of landscape management that gradually filled up the river channels with sediment. Who will help you? An army of scientists that each speak their own language! And of course the solutions are in spatial planning and governance, which are again separate sciences.

 

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