GeoLog

Natural Hazards

August GeoRoundUp: the best of the Earth sciences from around the web

August GeoRoundUp: the best of the Earth sciences from around the web

Drawing inspiration from popular stories on our social media channels, as well as unique and quirky research news, this monthly column aims to bring you the best of the Earth and planetary sciences from around the web.

Major Stories

On August 25th Hurricane Harvey made landfall along the southern coast of the U.S.A, bringing record breaking rainfall, widespread flooding and a natural disaster on a scale not seen in the country for a long time. In fact, it’s the first time since 2005 a major hurricane has threatened mainland U.S.A. – a record long period.

But Harvey’s story began long before it brought destruction to Texas and Louisiana.

On August 17th,the National Space Agency (NASA) satellite’s first spotted a tropical depression forming off the coast of the Lesser Antilles. From there the storm moved into the eastern Caribbean and was upgraded to Tropical Storm Harvey where it already started dropping very heavy rainfall. By August 21st, it had fragmented into disorganised thunderstorms and was spotted near Honduras, where heavy local rainfall and gusty winds were predicted.

Over the next few days the remnants of the storm travelled westwards towards Nicaragua, Honduras, Belize and the Yucatan Peninsula. Forecasters predicted that, owing to warm waters of the Gulf of Mexico and favorable vertical wind shear, there was a high chance the system could reform once it moved into the Bay of Campeche (in the southern area of the Gulf of Mexico) on August 23rd. By August 24th data acquired with NASA satellites showed Harvey had began to intensify and reorganise. Heavy rainfall was found in the system.

Harvey continued to strengthen as it traveled across the Gulf of Mexico and weather warnings were issued for the central coast of Texas. Citizens were told to expect life-threatening storm surges and freshwater flooding. On August 25th, Harvey was upgraded to a devastating Category 4 hurricane, when sustained wind speeds topped 215 kph.

Since making landfall on Friday and stalling over Texas (Louisiana is also affected) – despite being downgraded to a tropical storm as it weakened – it has broken records of it’s own. “No hurricane, typhoon, or tropical storm, in all of recorded history, has dropped as much water on a single major city as Hurricane Harvey is in the process of doing right now in Houston (Texas)”, reports Forbes. In fact, the National Weather Service had to update the colour charts on their graphics in order to effectively map it. This visualisation maps Harvey’s destructive path through Texas.

A snaptshot from the tweet by the official Twitter account for NOAA’s National Weather Service.

So far the death toll is reported to be between 15 to 23 people, with the Houston Police Chief saying 30,000 people are expected to need temporary shelter and 2,000 people in the city had to be rescued by emergency services (figures correct at time of writing).

Many factors contributed toward making Hurricane Harvey so destructive. “The steering currents that would normally lift it out of that region aren’t there,” J. Marshall Shepherd, director of the atmospheric sciences program at the University of Georgia, told the New York Times. The storm surge has blocked much of the drainage which would take rainfall away from inland areas. And while it isn’t possible to say climate change caused the hurricane, “it has contributed to making it worse”, says Michael E Mann. The director of the Earth System Science Center at Pennsylvania State University argues that rising sea levels and ocean water temperatures in the region (brought about by climate change) contributed to greater rainfall and flooding.

A man carries his cattle on his shoulder as he moves to safer ground at Topa village in Saptari. Credit: The Guardian.

While all eyes are on Houston, India, Bangladesh and Nepal are also suffering the consequences of devastating flooding brought about a strong monsoon. The United Nations estimates that 41 million people are affected by the disaster across the three countires. Over 1200 people are reported dead. Authorities are stuggling with the scale of the humanitarian crisis: “Their most urgent concern is to accessing safe water and sanitation facilities,” the UN Office for the Coordination of Humanitarian Affairs (OCHA) said earlier this week, citing national authorities. And its not only people at risk. Indian authorities reported large swathes of a famous wildlife reserve park have been destroyed. In Mumbai, the downpour caused a building to collapse killing 12 people and up to 25 more are feared trapped.Photo galleries give a sense of the scale of the disaster.

Districts affected by flooding. Credit: Guardian graphic | Source: ReliefWeb. Data as of 29 August 2017

What you might have missed

In fact, it’s highly unlikely you missed the coverage of this month’s total solar eclipse over much of Northern America. But on account of it being the second biggest story this month, we felt it couldn’t be left out of the round-up. We particularly like this photo gallery which boasts some spectacular images of the astronomical event.

This composite image, made from seven frames, shows the International Space Station, with a crew of six onboard, as it transits the Sun at roughly five miles per second during a partial solar eclipse, Monday, Aug. 21, 2017 near Banner, Wyoming. Credit: (NASA/Joel Kowsky)

Since the end of July, wildfires have been raging in southwest Greenland. While small scale fires are not unheard of on the island otherwise known for its thick ice cap and deep fjords, the fires this month are estimated to extend over 1,200 hectares. What started the fires remains unknown, as do the fuel sources and the long-term impacts of the burn.

The U.S.A’s National Oceanic and Atmospheric Administration highlighted that the fires are a source of sooty “black carbon”. As the ash falls on the pristine white ice sheet, it turns the surface black, which can make it melt faster. Greenland police recently reported that unexpected rain haf all but extinguished the massive fires; though the situation continues to be monitored, as smouldering patches run the risk of reigniting the flames.

 

 

 

Links we liked

The EGU story

Do you enjoy the EGU’s annual General Assembly but wish you could play a more active role in shaping the scientific programme? Now is your chance! Help shape the scientific programme of EGU 2018.

From today, until 8 Sep 2017, you can suggest:

  • Sessions (with conveners and description), or;
  • Modifications to the existing skeleton programme sessions
  • NEW! Suggestions for Short courses (SC) will also take place during this period
  • From now until 18 January 2018, propose Townhall and splinter meetings

And don’t forget! To stay abreast of all the EGU’s events and activities, from highlighting papers published in our open access journals to providing news relating to EGU’s scientific divisions and meetings, including the General Assembly, subscribe to receive our monthly newsletter.

 

New Dimensions for Natural Hazards in Asia: the first AOGS–EGU Joint Conference

New Dimensions for Natural Hazards in Asia: the first AOGS–EGU Joint Conference

Asia is one of the most natural disaster-prone regions on the globe. Overpopulation and limited resources mean that natural hazards hit local populations particularly hard.

“It doesn’t matter which index or evaluation method you use, Asia will always unfortunately come out on top when it comes to fatalities and damage from natural hazard events,” explains Dr. Adam Switzer, a member of the conference’s Executive Organizing Committee.

To provide a global platform, which brings together participants from across the world and addresses the challenges which need to be unraveled, as well as the potential solutions, the Asia Oceania Geosciences Society (AOGS) and EGU have partner to host their very first joint meeting.

With Taal Volcano as the spectacular backdrop, students, early career and established scientists will gather in the Philippines from the 4th to 8th February 2018, to discuss current advances in knowledge and new perspectives relevant to natural hazards in the Asian region.

“We hope that this conference will be a fundamental new step to addressing some of the most pressing hazard problems in the region by bringing together some of the world’s top hazard practitioners in the physical, social and political sciences,” goes on to say Switzer.

The meeting will boast an innovative format, with the organisers actively sidestepping the tradition conference triple Ss: sections, sessions and silos. Instead, the programme is arranged in a series of themes which, through panels, discussion groups, networking and poster introductions, will explore seven overarching topics: from natural hazards in the megacity, to multi-hazard interactions, right through to the transient and long-term effects of catastrophic perturbations.

Niels Hovius, also of the conference’s Executive Organizing Committee, adds: “we strive for a programme that explores the connectivity between processes, cause and effect, a programme that acknowledges the fact that many natural disasters have an important time dynamic, lasting much longer than the initial impact.”

The conference abstract submission is currently open, so if your research falls within one of the conference themes, consider contributing to the meeting. But hurry! Abstract submission closes on 31st August 2017.

As well as discussing and sharing advances in natural hazards science, conference participants will get the opportunity to experience the impacts of natural hazards first hand.

The Philippines is, unfortunately, rich with natural hazards and as such provides a wealth of opportunity to investigate the physical, social and economic aspects of numerous natural hazards through a series of conference field trips.  

“The recent earthquake in Bohol, the 1991 Pinatubo eruption and the devastation and recovery from 2013 Typhoon Haiyan are all part of the field program,” highlights Switzer.

Not only that, the conference takes place in a sought-after location, by tourists and locals alike. The Taal Vista Hotel is deeply rooted in the heritage of Tagaytay City. Overlooking Lake Taal, with views which stretch out over Taal volcano, it is also only a little over an hour away from the bustling city of Manila.

“There are a large range of very affordable to more luxurious accommodations available in Tagatay, although early booking is encouraged as the area is a popular one for tourism due to its environmental beauty,” points out Bruce Malamud, of the conference’s Executive Organizing Committee.

The AOGS-EGU conference is accessible and affordable for both early career and more senior researchers from around the globe. It hopes to bring together the international research community, with the scientific programme, as well as its spectacular setting, suited to natural hazard scholars and practitioners alike.

The Executive Organizing Committee also hopes that its appeal will transcend the geosciences and that the meeting’s themes will attract those dealing with other aspects of natural disasters: medics, planners, managers, educators and more.

“It is important that we have dialogues that reach beyond the confines of our disciplines,” says Hovius, “For me, this conference will be an opportunity to see some iconic sites, but also to make contacts with local researchers who may be interested in joining international projects targeting multi-hazards, transient response and anomalous events.”

Visit the conference website for all the meeting details. Among the website pages you’ll find information about the conference themes, abstract submission requirements and an overview of the meeting programme. Early bird registrations (until 23rd November 2017) receive a heavily discounted rate, as do AOGS and EGU members. Students also benefit from reduced registration fees.

The website is also packed with logistical information, from details about the conference venue, through to what you can expect to eat, see and do in Tagaytay City. You can also find out if you require a visa for travel to the Philippines and what to do if you are a national of a non-visa exempt country.

By Laura Roberts (EGU Communications Officer) in collaboration with the AOGS–EGU Joint Conference Executive Organizing Committee

For inquiries about the conference please contact Meeting Matters International (nathazards@meetmatt.net). Further contact information is available on the Joint Conference website. You can also receive updates about the conference on Facebook.

Imaggeo on Mondays: Sediments make the colour

Imaggeo on Mondays: Sediments make the colour

Earth is spectacularly beautiful, especially when seen from a bird’s eye view. This image, of a sweeping pattern made by a river in Iceland is testimony to it.

The picture shows river Leirá which drains sediment-loaded glacial water from the Myrdalsjökull glacier in Iceland. Myrdalsjökull glacier covers Katla, one of Iceland’s most active and ice-covered volcanoes.

A high sediment load (the suspended particles which are transported in river water) is typical for these glacial rivers and is visible as the fast-flowing glacial river (on the right of this image) appears light brown in colour. The sediment is gradually lost in the labyrinth of small lakes and narrow, crooked connections between lakes as can be seen as a gradual change in colour to dark blue.

The sediment load, height of the water  and chemistry of this and other glacial rivers are measured partly in real-time by the Icelandic Meteorological Office. This is done for research purposes and in order to detect floods from subglacial lakes that travel up to several tens of kilometers beneath the glacier before they reach a glacial river.

These glacial outburst floods do not only threaten people, livestock and property, but also infrastructure such as Route 1, a circular, national road which runs around the island. They occur regularly due to volcanic activity or localized geothermal melting on the volcano, creating a need for an effective early-warning system.

Advances in the last years include the usage of GPS instruments on top of a subglacial lake and the flood path in order to increase the early-warning for these floods. In 2015, the GPS network, gave scientists on duty at the Icelandic Meteorological Office 3.5 days of warning before one of the largest floods from western Vatnajökull emerged from beneath the ice.

The peak discharge exceeded 2000 m3/s,  which is comparable to an increase in discharge from that of the Thames to that of the Rhine.  This flood was also pioneeringly monitored with clusters of seismometers, so called arrays (from University College Dublin & Dublin Institute for Advanced Studies, Ireland), that enabled an early-warning of at least 20 hours and allowed to track the flood front merely using the ground vibrations it excited. The flood propagated under the glacier at a speed of around 2 km/h; so assuming you can keep up the speed over nearly a day you can escape the flood by walking while it is moving beneath the glacier.

Related publications about the tracking of these subglacial floods will emerge in the published literature soon (real time update available at www.evapseibl.wordpress.com).

By Eva Eibl, researcher at the Dublin Institute for Advanced Studies.

Thanks go to www.volcanoheli.is who organised this trip.

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/.

 

GeoSciences Column: Is smoke on your mind? Using social media to assess smoke exposure from wildfires

GeoSciences Column: Is smoke on your mind? Using social media to assess smoke exposure from wildfires

Wildfires have been raging across the globe this summer. Six U.S. States, including California and Nevada, are currently battling fierce flames spurred on by high temperatures and dry conditions. Up to 10,000 people have been evacuated in Canada, where wildfires have swept through British Columbia. Closer to home, 700 tourists were rescued by boat from fires in Sicily, while last month, over 60 people lost their lives in one of the worst forest fires in Portugal’s history.

The impacts of this natural hazard are far reaching: destruction of pristine landscapes, costly infrastructure damage and threat to human life, to name but a few. Perhaps less talked about, but no less serious, are the negative effects exposure to wildfire smoke can have on human health.

Using social media posts which mention smoke, haze and air quality on Facebook, a team of researchers have assessed human exposure to smoke from wildfires during the summer of 2015 in the western US. The findings, published recently in the EGU’s open access journal Atmospheric Chemistry and Physics, are particularly useful in areas where direct ground measurements of particulate matter (solid and liquid particles suspended in air, like ash, for example) aren’t available.

Particulate matter, or PM as it is also known, contributes significantly to air quality – or lack thereof, to be more precise.  In the U.S, the Environment Protection Agency has set quality standards which limit the concentrations of pollutants in air; forcing industry to reduce harmful emissions.

However, controlling the concentrations of PM in air is much harder because it is often produced by natural means, such as wildfires and prescribed burns (as well as agricultural burns). A 2011 inventory found that up to 20% of PM emissions in the U.S. could be attributed to wildfires alone.

Research assumes that all PM (natural and man-made) affects human health equally. The question of how detrimental smoke from wildfires is to human health is, therefore, a difficult one to answer.

To shed some light on the problem, researchers first need to establish who has been exposed to smoke from natural fires. Usually, they rely on site (ground) measurements and satellite data, but these aren’t always reliable. For instance, site monitors are few and far between in the western US; while satellite data doesn’t provide surface-level concentrations on its own.

To overcome these challenges, the authors of the Atmospheric Chemistry and Physics paper, used Facebook data to determine population-level exposure.

Fires during the summer of 2015 in Canada, as well as Idaho, Washington and Oregon, caused poor air quality conditions in the U.S Midwest. The generated smoke plume was obvious in satellite images. The team used this period as a case study to test their idea.

Facebook was mined for posts which contained the words ‘smoke’,’smoky’, ‘smokey’, ‘haze’, ‘hazey’ or ‘air quality’. The results were then plotted onto a map. To ensure the study was balanced, multiple posts by a single person and those which referenced cigarette smoke or smoke not related to natural causes were filtered out. In addition, towns with small populations were weighted so that those with higher populations didn’t skew the results.

The social media results were then compared to smoke measurements acquired by more traditional means: ground station and satellite data.

Example datasets from 29 June 2015. (a) Population – weighted, (b) average surface concentrations of particulate matter, (c) gridded HMS smoke product – satellite data, (d) gridded, unfiltered MODIS Aqua and MODIS Terra satellite data (white signifies no vaild observation), and (e) computer simulated average surface particulate matter. Image and caption (modified) from B.Ford et al., 2017.

The smoke plume ‘mapped out’ by the Facebook results correlates well with the plume observed by the satellites. The ‘Facebook plume’ doesn’t extend as far south (into Arkansas and Missouri) as the plume seen in the satellite image, but neither does the plume mapped out by the ground-level data.

Satellites will detect smoke plumes even when they have lifted off the surface and into the atmosphere. The absence of poor air quality measurements in the ground and Facebook data, likely indicates that the smoke plume had lifted by the time it reached Arkansas and Missouri.

The finding highlights, not only that the Facebook data can give meaningful information about the extend and location of smoke plume caused by wildfires, but that is has potential to more accurately reveal the air quality at the Earth’s surface than satellite data.

The relationship between the Facebook data and the amount of exposure to particular matter is complex and more difficult to establish. More research into how the two are linked will mean the researchers can quantify the health response associated with wildfire smoke. The findings will be useful for policy and decision-makers when it comes to limiting exposure in the future and have the added bonus of providing a cheap way to improve the predictions, without having to invest in expanding the ground monitor network.

By Laura Roberts, EGU Communications Officer

References

Ford, B., Burke, M., Lassman, W., Pfister, G., and Pierce, J. R.: Status update: is smoke on your mind? Using social media to assess smoke exposure, Atmos. Chem. Phys., 17, 7541-7554, https://doi.org/10.5194/acp-17-7541-2017, 2017.

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