NH
Natural Hazards
Gabriele Amato

Gabriele Amato

My name is Gabriele Amato I am from Rome (Italy) where I studied geology and where I have just finished my PhD, at Roma Tre University. My research is about landslide monitoring through terrestrial and satellite techniques, in different geological and geomorphological contexts. The aim of my PhD was to relate the landslides movement to their triggering factors (rainfall, earthquakes, temperature variations). I am passionate about natural hazards and methods to manage them, especially remote sensing based. In my role as author of the NH blog I am looking forward to sharing course and initiatives organised all around the world in the field of natural hazards with the scientific community, and especially young researchers, since I think these represent great opportunities for networking.

InSAR Norway: the big eye on Norwegian unstable rock slopes

InSAR Norway: the big eye on Norwegian unstable rock slopes

Marie Keiding is a researcher in the Geohazard and Earth Observation team at the Geological Survey of Norway. Together with her colleague, John Dehls, who is leading the project, she works to develop and operate the new mapping service called InSAR Norway.

Before we start, let’s briefly describe what is InSAR. First, the Synthetic Aperture Radar (SAR) is a day and night operational imaging system that can be operated from satellite aircraft or ground and has high capabilities of penetrating clouds because it uses microwaves. Its ‘interferometric configuration’, Interferometric SAR or InSAR, uses two or more SAR images to generate maps of surface deformation or digital elevation models. This is made by calculating differences in the phase of the waves returning to the sensor, as a function of the satellite position and time of acquisition.

Measurements of phase variations are possible only in those pixels of the image where the signal maintains a sufficient coherence between different acquisitions. For this reason, InSAR techniques are particularly suitable to monitor relatively small deformations, in the order of millimetres to centimetres.

Hi Marie, can you tell what is InSAR Norway?

InSAR Norway is the first free and open, nationwide, [Read More]

Landslide forecasting and warning service in Norway

Today our blog will host Graziella Devoli who will tell us about the Landslide Forecasting and Warning Service currently operating in Norway by the Norwegian Water Resources and Energy Directorate (NVE). Graziella is Senior Geologist at NVE and she has PhD in Environmental Geology and Geohazards obtained at the University of Oslo (UiO) where she also teaches in the Geohazards master program. At NVE she works with the organization and development of the national forecasting service and in the daily landslide hazard assessment. Her expertise in this field comes from the years spent working in Nicaragua in natural risk management and emergency planning, where she experienced the importance of adopting multi-disciplinary approaches and strengthening national and international collaboration in disaster risk reduction. Since few years she shares her experience in class organizing a serious game where, using a multi-hazard case study, students analyse roles and responsibility of different stakeholders in disaster preventive actions. The exercise is given to UiO-students and to early career scientists at EGU conference.

Hi Graziella and thank you for being with us. Would you tell us what varsom.no is?

Varsom in Norwegian means “cautious” and Varsom.no is the Norwegian national web portal where daily flood, landslides, snow avalanches warnings and ice conditions on a regional scale are published and represents the main channel to communicate bulletins and warning levels to end-users. [Read More]

Earthquake-induced landslides and the ‘strange’ case of the Hokkaido earthquake

The population of many countries in the world is exposed to earthquakes, one of the most destructive natural hazards. Sometimes, consequent triggered  phenomena can be even worse than the earthquake itself. In this context, earthquake-induced landslides often concur in life and economic losses. To better understand these induced phenomena, updated catalogues of their types and location of occurrence are fundamental. In his works, Dr David K. Keefer performed several interesting statistical analysis, which highlighted how the magnitude and the distance from the epicentre play a key role in triggering earthquake-induced landslides (Figs. 1 and 2). In particular, he showed that the number of landslides induced by earthquakes decreases with the increase in distance from the epicentre (Fig.1) and that the number of landslide increases with larger magnitude events (Fig. 2). [Read More]

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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