Yorkshire volcanic ash helps to improve flight safety forecasts


Dr Graeme Swindles on a fieldwork trip at Malham Tarn Moss, Yorkshire Dales, where microscopic ash layers from prehistoric eruptions in Iceland were found. Credit: Paul J. Morris

Predictions of where planes can safely fly following volcanic eruptions could be improved, thanks to fresh discoveries about ash clouds.

To study the size of ash grains and how far they can travel, scientists at the Met Office and the Universities of Leeds, Edinburgh and Iceland, compared grains recovered from recent Icelandic eruptions – including samples recovered in Yorkshire – with satellite measurements of ash clouds.

Their findings, published today in Atmospheric Measurement Techniques, will help to improve methods of mapping ash concentration in order to identify zones where it is safe to fly during future eruptions.

Hundreds of flights were cancelled in 2010 and 2011 following volcanic activity in Iceland because of the danger that volcanic ash posed to aircraft and their engines.

In the new study, researchers studied volcanic ash recovered in the UK from the recent Eyjafjallajökull and Grímsvötn eruptions, as well as prehistoric samples from peat bogs in Yorkshire, Scotland and Ireland. Another sample, from an 1875 eruption, had been in a museum for 140 years.

The researchers found that grains were much larger than what had been typically estimated by satellite measurements of ash clouds – even moderately-sized eruptions could disperse large grains as far as the UK.

Volcanic ash particles from Icelandic eruptions extracted from peat bogs in Malham, Yorkshire, (pictures ‘a’ and ‘d’) and the Shetland Islands, Scotland (pictures ‘b’ and ‘c’). Credit: Atmospheric Measurement Techniques

Study co-author Dr Graeme Swindles, from the School of Geography at the University of Leeds, said: “Microscopic volcanic ash layers preserved in Yorkshire peat bogs and mud at the bottom of lakes, far from volcanoes, are providing much needed information on the characteristics of ash clouds. These records show us that Europe was hit by volcanic ash clouds very frequently in the past.”

The group also used computer models to simulate how clouds of various ash particle sizes would appear to satellite sensors. They found that sensors can underestimate the size of larger particles.

Dr John Stevenson, of the University of Edinburgh’s School of GeoSciences, who led the study, said: “Mapping volcanic ash clouds and their risk to aircraft is hard. Large regions of airspace can be contaminated by particles that are invisible to the naked eye. Combining the expertise of volcanologists and atmospheric scientists should help improve forecasts.”


Further information

The study was supported by the Scottish Government and Marie Curie Actions via the Royal Society of Edinburgh.

The research paper, ‘Big grains go far: understanding the discrepancy between tephrochronology and satellite infrared measurements of volcanic ash’, is published online in the journal Atmospheric Measurement Techniques on 19 May 2015.

Dr Graeme Swindles is available for interview. Please contact Sarah Reed, Press Officer at the University of Leeds, on 0113 34 34196 or email s.j.reed@leeds.ac.uk.

When continents collide: Active deformation and seismic hazard

Since 1900, 35 earthquakes worldwide have each killed at least 10,000 people. Of these, 26 were in the Alpine-Himalayan seismic belt – a broad “crumple zone” where the African, Arabian and Indian tectonic plates collide with Europe and Asia. Most of these deadly earthquakes were caused by the rupture of faults that had not previously been identified.

CGS scientist Tim Wright is Professor of Satellite Geodesy at the University of Leeds and Director of the Natural Environment Research Council’s Centre for the Observation and Modelling of Earthquakes, Volcanoes and Tectonics (COMET). His work has been at the forefront of developing the use of satellite radar for measuring tectonic and volcanic deformation.

Tim was recently invited to present a guest lecture at the Geological Society on his work trying to understand the nature of seismic hazard within the Alpine-Himalayan region.

You can follow Tim on twitter: @timwright_leeds

Nepal earthquake lowered Everest by up to 2.5 cm

Further analysis of the newly processed sentinel-1 satellite radar data shows that the area around the Kathmandu region was uplifted in the earthquake, while the area to the north of Kathmandu sunk (subsided).

The red region in the image below shows uplift while the faint blues to the north indicate subsidence. Mount Everest is located to the northeast of Kathamndu.

Processed Sentinel 1 results of the Nepal earthquake deformation. red = mostly subsidence, blue = mostly uplift.  Source: Pablo Gonzalez – LiCS/COMET+

Processed Sentinel-1 results of the Nepal earthquake deformation. red = mostly uplift, blue = mostly subsidence.
Source: Pablo GonzalezLiCS/COMET+


The image was produced by COMET researchers at the University of Leeds as part of the Look Inside the Continents from Space (LiCS) project led by CGS scientist Professor Tim Wright.

New computer modelling results estimate that the amount of lowering experienced in the Everest region could be up to 2.5cm. These numbers are very preliminary and will be verified over the coming days with further research.

Clearer sentinel 1 image of Nepal earthquake deformation

A new clearer sentinel 1 satellite image has been produced by COMET researchers as part of the Look Inside the Continents from Space (LiCS) project led by CGS scientist Professor Tim Wright.

For Tim Wright’s preliminary interpretation of the results see our previous post.

Sentinel 1 image of the Nepal earthquake deformation. Source: John Elliot - LiCS/COMET

Sentinel 1 image of the Nepal earthquake deformation. 1 colour fringe = 10cm of ground deformation.
Source: John ElliotLiCS/COMET+

First Sentinel 1 satellite results for Nepal earthquake

The first coseismic sentinel 1 satellite results have now been processed by researchers in the InSARap project.

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[edit] For a sharper image of the ground deformation see our latest post.

Tim Wright, CGS scientist and professor of satellite geodesy at the University of Leeds has provided a preliminary interpretation of the new results.

1. The earthquake ruptured East from the epicentre, confirming the observations from seismology.

2. Peak displacement is very close to Kathmandu; the fault under the city slipped significantly.

3. An area at least 120×50 km uplifted, with a maximum slip greater than 1m

4. The fault did not rupture the surface.

5. Area north of Kathmandu subsides. Consistent with elastic rebound from shallow thrust.
[CORRECTION]: The area around Kathmandu is uplifted in the earthquake

6. Overall, area at least 120 x100 km moved. Sentinel-1 data invaluable at this scale.

8 million in need of humanitarian aid in Nepal

8 million people in need of humanitarian assistance in Nepal after a powerful magnitude 7.8 earthquake shook the country on April 25th, according to the United Nations Office for the Coordination of Humanitarian affairs (UN OCHA).

Key numbers in need of aid. Source: UN OCHA

Key numbers in need of aid.
Source: UN OCHA

Click on the image below for a link to how best to donate towards aid efforts in Nepal.

More information:
[1] http://www.unocha.org/nepal

Tiny microbes on glaciers cause positive feedback for climate change

Tiny microbial activity on glaciers in the Arctic is reducing heat reflected back into the atmosphere. This effect has previously been overlooked but is expected to increase the effects of climate change in the polar regions.

Over the past few years Professor Liane G. Benning and PhD student Stefanie Lutz, members of the Cohen geochemistry research group in the School of Earth and Environment, have been busy making trips to Svalbard and Iceland to measure the ‘albedo’, the reflectivity, of glaciers and how microbial gardens might effect the amount of sunlight reflected by the glacier.

They discussed their recent trip to Svalbard with BBC’s Paul Hudson on his Weather Show radio channel. As well as talk about watching a solar eclipse from the the North, polar bear attacks, northern lights and news on a big new grant to study glaciers in Greenland!

Remembering the Colombia 1985 volcanic disaster

One of the most tragic volcanic events of the 20th century occurred in Colombia, in 1985, when an eruption of Nevado del Ruiz produced lahars that swept down river valleys and destroyed communities in its path. Over 20,000 people perished.

Mount Rainier and other volcanoes of the Pacific Northwest’s Cascade Range are similar to Nevado del Ruiz in many respects—massive amounts of snow and ice, a long history of lahars, and narrow valleys leading to populated areas. Could what happened at Nevado del Ruiz happen in the Pacific Northwest? And if it did, are we prepared?

In 2013, the US-Colombia Bi-national Exchange was created to help scientists, emergency managers and first responders in both countries to learn from the events in Colombia and to work toward improving disaster preparedness in communities located near volcanoes. The Exchange allows the Colombian officials to observe and learn about U.S. emergency response systems and for U.S. personnel to absorb the hard-earned lessons from the Colombians’ experiences with volcanic crises.

Scientists, decision-makers, emergency officials, community leaders, teachers, parents, students—everyone has a responsibility to prepare for the next eruption. Your role in preparedness begins with learning about the hazards where you live, work or go to school, evacuation routes and how to access information during a crisis. Ask local and state emergency officials and schools about their plans and be ready to follow their guidance. Finally, gather basic emergency provisions and create a plan to reunite with family members if you are separated. The volcano may erupt, but the tragedy doesn’t have to happen. And that is the point.

New long term earthquake forecast for California

The United States Geological Survey (USGS) have released a new long term earthquake forecast for the U.S. state of California. The new study revises previous estimates for the chances of having large earthquakes over the next several decades.

USGS scientists working on the project estimate the frequency of a magnitude 6.7 earthquake, the size of the destructive 1994 Northridge earthquake, to occur around every 6.3 years. This is slightly larger than previous estimates of 4.8 years.

However, in the new study, the estimate for the likelihood that California will experience a magnitude 8 or larger earthquake in the next 30 years has increased from about 4.7 percent to about 7 percent.

Uniform California Earthquake Rupture Forecast (Version 3). Source: USGS

Uniform California Earthquake Rupture Forecast (Version 3).
Source: USGS

More Information:
[1] http://www.usgs.gov/newsroom/article.asp?ID=4146&from=rss#.VQvy5ESA9vx
[2] http://www.wgcep.org/UCERF3