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GeoTalk: A smart way to map earthquake impact

GeoTalk: A smart way to map earthquake impact

Last week at the 2016 General Assembly Sara, one of the EGU’s press assistants, had the opportunity to speak to Koen Van Noten about his research into how crowdsourcing can be used to find out more about where earthquakes have the biggest impact at the surface.

Firstly, can you tell me a little about yourself?

I did a PhD in structural geology at KULeuven and, after I finished, I started to work at the Royal Observatory of Belgium. What I do now is try to understand when people feel an earthquake, why they can feel it, how far away from the source they can feel it, if local geology affects the way people feel it and what the dynamics behind it all are.

How do you gather this information?

People can go online and fill in a ‘Did You Feel It?’ questionnaire about their experience. In the US it’s well organised because the USGS manages this system in whole of the US. In Europe we have so many institutions, so many countries, so many languages that almost every nation has its own questionnaire and sometimes there are many inquiries in only one country. This is good locally because information about a local earthquake is provided in the language of that country, but if you have a larger one that crosses all the borders of different countries then you have a problem. Earthquakes don’t stop at political borders; you have to somehow merge all the enquiries. That’s what I’m trying to do now.

European institutes that provide an online "Did You Feel the Earthquake?" inquiry. (Credit: Koen Van Noten)

European institutes that provide an online “Did You Feel the Earthquake?” inquiry. (Credit: Koen Van Noten)

There are lots of these databases around the world, how do you combine them to create something meaningful?

You first have to ask the different institutions if you can use their datasets, that’s crucial – am I allowed to work on it? And then find a method to merge all this information so that you can do science with it.

You have institutions that capture global data and also local networks. They have slightly different questions but the science behind them is very similar. The questions are quite specific, for instance “were you in a moving vehicle?” If you answer yes then of course the intensity of the earthquake has to be larger than one felt by somebody who was just standing outside doing nothing and barely felt the earthquake. You can work out that the first guy was really close to the epicentre and the other guy was probably very far, or that the earthquake wasn’t very big.

Usually intensities are shown in community maps. To merge all answers of all institutes, I avoid the inhomogeneous community maps. Instead I use 100 km2 grid cell maps and assign an intensity to every grid cell.. This makes the felt effect easy to read and allows you to plot data without giving away personal details of any people that responded. Institutes do not always provide a detailed location, but in a grid cell the precise location doesn’t matter. It’s a solution to the problem of merging databases within Europe and also globally.

Underlying geology can have a huge impact on how an earthquake is felt.  Credit: Koen Van Noten.

Underlying geology can have a huge impact on how an earthquake is felt. 2011 Goch ML 4.3 earthquake.  Credit: Koen Van Noten.

What information can you gain from using these devices?

If you make this graph for a few earthquakes, you can map the decay in shaking intensity in a certain region. I’m trying to understand how the local geology affects these kinds of maps. Somebody living on thick pile of sands, several kilometres above the hypocentre, won’t feel it because the sands will attenuate the earthquake. They are safe from it. However, if they’re directly on the bedrock, but further from the epicentre, they may still feel it because the seismic waves propagate fast through bedrock and aren’t attenuated.

What’s more, you can compare recent earthquakes with ones that happened 200 years ago at the same place. Historical seismologists map earthquake effects that happened years ago from a time when no instrumentation existed, purely based on old personal reports and journal papers. Of course the amount of data points isn’t as dense as now, but even that works.

Can questionnaires be used as a substitute for more advanced methods in areas that are poorly monitored?

Every person is a seismometer. In poorly instrumented regions it’s the perfect way to map an earthquake. The only thing it depends on is population density. For Europe it’s fine, you have a lot of cities, but you can have problems in places that aren’t so densely populated.

Can you use your method to disseminate information as well as gather it, say for education?

The more answers you get, the better the map will be. Intensity maps are easier to understand by communities and the media because they show the distribution of how people felt it, rather than a seismogram, which can be difficult to interpret.

What advice would you give to another researcher wanting to use crowd-sourced information in their research?

First get the word out. Because it’s crowd-sourced, they need to be warned that it does exist. Test your system before you go online, make sure you know what’s out there first and collaborate. Collaborating across borders is the most important thing to do.

Interview by Sara Mynott, EGU Press Assistant and PhD student at Plymouth University.

Koen presented his work at the EGU General Assembly in Vienna. Find out more about it here.

Imaggeo on Mondays: a big thank you from the EGU

Outside EGU General Assembly 2016. Credit: Kai Boggild/EGU (distributed via imaggeo.egu.eu)

The past week in Vienna was a busy one! Hordes of Earth, ocean and planetary scientists came together to present, share and discuss their most recent scientific findings at the 2016 General Assembly.

The conference was a great success, with over 4800 oral and 10300 poster presentations, as well as close to a 1000 PICO presentations too! Participants at the conference could pick talks and posters from a staggering selection of over 600 scientific sessions, as well as in excess of 300 side events. The programme in 2016 was indeed rich and varied! Helping participants choose from the vast selection of science on offer, 15,000 copies of EGU Today were distributed throughout the week.

The conference was attended by 13,650 scientists from 109 countries, of which 25% were students and 53% early career scientists (under the age of 35 years). There was also a keen media presence and reporting, and thousands of visits to the webstreams as well as to GeoLog.

We thank all of you very much for your attendance and your active contribution to this great event.

We look forward to seeing you all next year! The EGU General Assembly is back from 23–28 April 2017 in Vienna, Austria.

Communicate Your Science Competition Winner Announced!

Congratulations to Beatriz Gaite, the winner of the Communicate Your Science Video Competition 2016. Beatriz is a researcher at the department of Earth’s Structure and Dynamics and Crystallography at the Instituto de Ciencias de la Tierra Jaume Almera (ICTJA-CSIC), in Spain.

Want to communicate your research to a wider audience and try your hand at video production? Early career scientists  who pre-registered for the 2017 EGU General Assembly are invited to take part in the EGU’s Communicate Your Science Video Competition! Find out more – importantly, when to submit your entries – about the competition!

Announcing the winners of the EGU Photo Contest 2016!

Announcing the winners of the EGU Photo Contest 2016!

The selection committee received over 200 photos for this year’s EGU Photo Contest, covering fields across the geosciences. Participants at the 2016 General Assembly have been voting for their favourites throughout the week  of the conference and there are three clear winners. Congratulations to 2016’s fantastic photographers!

 Glowing_Ice. Credit:  Vytas Huth (distributed via  imaggeo.egu.eu). Ice on Jokulsarlon beach in Iceland. Ice calving off the Breidamerkurjokull, one of the glaciers comprising the Vatnajokull, the largest glacier in Iceland. The is retreating rapidly, and in the process has created a large glacial lagoon known for its spectacular icebergs.

Glowing_Ice. Credit: Katharine Cashman (distributed via imaggeo.egu.eu). Ice on Jokulsarlon beach in Iceland. Ice calving off the Breidamerkurjokull, one of the glaciers comprising the Vatnajokull, the largest glacier in Iceland. The is retreating rapidly, and in the process has created a large glacial lagoon known for its spectacular icebergs.

 'Living flows'. Credit:  Marc Girons Lopez (distributed via  imaggeo.egu.eu). River branches and lagoons in the Rapa river delta, Sarek National Park, northern Sweden. The lush vegetation creates a stark contrast with the glacial sediments transported by the river creating a range of tonalities.

Living flows’. Credit: Marc Girons Lopez (distributed via imaggeo.egu.eu). River branches and lagoons in the Rapa river delta, Sarek National Park, northern Sweden. The lush vegetation creates a stark contrast with the glacial sediments transported by the river creating a range of tonalities.

 'There is never enough time to count all the stars that you want.' . Credit:  Vytas Huth (distributed via  imaggeo.egu.eu). The centre of the Milky Way taken near Krakow am See, Germany. Some of the least light-polluted atmosphere of the northern german lowlands.

‘There is never enough time to count all the stars that you want.’ . Credit: Vytas Huth (distributed via imaggeo.egu.eu). The centre of the Milky Way taken near Krakow am See, Germany. Some of the least light-polluted atmosphere of the northern german lowlands.

In addition, this year, to celebrate the theme of the EGU 2016 General Assembly, Active Planet, the photo that best captured the theme of the conference was selected by the judges. The winner is the stunning ‘Mirror Mirror in the sea’, by Mario Hopmann! Congratulations! Scroll to the top of this post to view Mario’s image.

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

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