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Natural Hazards

Archives / 2018 / July

Hazard chains: from anthropic oil spills to ecosystem pollution. Can tiny organisms be the solution?

Hazard chains: from anthropic oil spills to ecosystem pollution. Can tiny organisms be the solution?

Hello to everyone. Today I have the personal pleasure to interview Dr. Grégoire Michoud. He is a friend and a brilliant scientist working on ecosystem microbial ecology. In the interview, Grégoire will talk to us about oil spills in the marine system, a specific anthropic hazard that can evolve into a natural hazard with terrible environmental consequences.

Grégoire Michoud is a Post-Doctoral Scientist at KAUST (Saudi Arabia), since 2015. He obtained his Ph.D. from the Université de Bretagne Occidentale, in Brest France. His primary research interest focuses on the characterization of the coping mechanisms of microbes in extreme environments (deep sea, brine pools, hydrocarbon pollution) by genomics and cultures approaches. His work has application in hazard chain from anthropic sources to natural targets.

 

 

Hello Grégoire, please tell us a bit about environmental issues related to oil spills.

When it comes to oil spills, widespread publicized releases are rare events and represent just 10% of the overall release in the marine ecosystem. The remaining 90% is actually due to ship activities or other land-based industries that contribute to the pollution. One example of rare oil spill is the Deep Water Horizon case where, in a relative short time, a huge amount of oil was released into the Gulf of Mexico. However, in the vast majority of situations, small quantities of oil can be released from random events adding up to a considerable pollution.

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How to study Mega-earthquakes? By generating them!

Dr. Francesca Funiciello

Francesca Funiciello is an Associated Professor at Roma Tre University (Rome, Italy). Her research interests are, among others, geodynamics, seismotectonics, rheology of analogue materials and science communication. She leads an active and young research group composed by Fabio Corbi, Silvia Brizzi and Elenora van Rijsingen, and collaborates with many other young and experienced researchers in Europe. The main activities of Francesca, Fabio, Silvia and Elenora involve analogue and numerical modelling of subduction zones, geophysical data analysis and geostatistics in the field of mega-earthquakes.

 

 

  1. Hi guys, can you tell us a bit more about “mega-earthquakes” and why it is so important to study them?

The interface between the subducting and overriding plates (Fig.1), the so-called megathrust, hosts the largest earthquakes on our planet Earth. They are generally called mega-earthquakes, with the prefix ‘mega’ highlighting both the fault originating them and their size. A quite recent example of a mega-earthquake is the Sumatra-Andaman event that occurred in 2004. The length of the fault that ruptured was ca. 1000 km and it generated a magnitude in the range of Mw 9.1–9.3 (Lay et al., 2005; Stein & Okal 2005; Subarya et al., 2006; Fujii & Satake 2007), where Mw denotes moment magnitude, a logarithmic measure of earthquake size. There had not been an event so large since the 1964 Alaska earthquake. The energy released during the Sumatra-Andaman 2004 event was in the range 5–10×1022 Nm—equivalent to the sum of the moment of all earthquakes in the preceding decade, worldwide (Lay et al., 2005).

 

Figure 1 – Schematic section through a subduction zone. The interface between the overriding and subducting plate is the so-called megathrust. The red star highlights the hypocenter of a megathrust earthquake (courtesy of S. Brizzi).

 

Subduction mega-earthquakes (together with the tsunamis they may generate) are among the largest hazards for human life, considering that millions of people live in proximity of subduction zones (e.g., the NE-Japanese and South American subduction zones), which are located at the edges of the Pacific Ocean.

 

  1. Which approach does the scientific community adopt to study mega-earthquakes? 

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The emergency of disaster emergency planning

The emergency of disaster emergency planning

Today I have the honour to introduce Prof. David Alexander as our guest. David is Professor of Risk and Disaster     Reduction at University College London (UK). His expertise comprises holistic aspects of disaster risk reduction and practical matters in emergency planning and management. He has also worked as Scientific Director of the Advanced School of Civil Protection of the regional government of Lombardy (Italy). As a Professor at the University of Florence (2005-11) he was a leading member of the team that designed, launched and taught Italy’s first Master of Civil Protection course.

David Alexander is the founder and Editor-in-Chief of Elsevier’s International Journal of Disaster Risk Reduction and was formerly Co-Editor of Disasters journal. He is Vice-President and Chairman of the Trustees of the Institute of Civil Protection and Emergency Management, which is the oldest learned society in the field of disaster reduction. He strongly supports the idea that “we are part of the civil-protection process. […] Therefore, we should all prepare for the next disaster as remarkably few of us will be able entirely to avoid it”.

 

  1. How can we define ‘disaster emergency’?

Not all emergencies are disasters. Two books have been written on the topic of ‘What is a disaster?’, which shows that the definition is open to many different interpretations. An emergency can be defined as a situation caused by a threat or hazard that cannot be managed with ordinary, workaday procedures and resources. It requires rapid response via a qualitative change in the way things are done. Most emergencies involve actual or potential (i.e. imminent) damage and destruction, or at least serious disruption, and possibly casualties.

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