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Imaggeo on Mondays: On the way to Tristan’s penguins

Imaggeo on Mondays: On the way to Tristan’s penguins

Tristan da Cunha is a remote volcanic island in the south Atlantic Ocean. In fact, it is the most remote inhabited archipelago in the world. Tristan is still volcanically active; the last time it erupted was in 1961. After the eruption, which luckily did not have any casualties, the whole population of around 260 people evacuated the island for some time, but they all returned back to the island because it was home.

I took this photo while aboard the ISOLDE research cruise associated with the GEOMAR Helmholtz Centre for Ocean Research in Germany. The ISOLDE project focuses on investigating the electromagnetic, gravimetric and seismic activity present on this little island.

There are several reasons why this area is particularly interesting for multi-disciplinary geophysical studies. First, the island is a prominent candidate for a deep-rooted hot spot. A hot spot is a volcanic region believed to be fed by mantle plumes, which bring considerable heat from deep in the Earth. Deploying ocean bottom seismometers (OBS) should help investigate the presence (or absence) of a whole-mantle plume beneath the island. Second, geophysical analysis in this region can help scientists better understand the tectonic processes involved in the extension of the South Atlantic margins and the formation of the Walvis Ridge.

In 2012, the ISOLDE (as part of the SAMPLE project) research cruise aimed to acquire a year’s worth of data on the marine electromagnetic activity, active and passive seismicity, gravity and bathymetry around Tristan da Cunha. Among others, there were 24 OBS deployed on the sea floor (around 3000-4000 m in depth). These instruments stay on the ocean bottom for one year and continuously record seismic signals.

After one year, in 2013, I joined the recovery cruise. This was my second time on a research vessel, but it was the first time I actually worked as a technical assistant on OBS.

The cruise started from Walvis Bay, a coastal town in Namibia. After a one-week transit from the harbour to the first station, we spent around seven days recovering 12 OBS around Tristan da Cunha.

The process of recovering the instruments is usually straight forward. To start, you head to the location where you first deployed the instrument, put a transducer into the water and then ping the OBS. If you get a response, you enter a code that sends an acoustic signal to release the main instrument from its steel anchor. The floating units attached to the instrument then take care of bringing the OBS back to the sea surface. Depending on the depth, it can take up to an hour until the OBS resurfaces (e.g. this is a simple calculation: 3000m deep, rising velocity of 1 m/s).

This would be a perfect recovery procedure, but you know, it rarely happens like this! After recovering half of the instruments over the course of about a week, the team got a well-deserved day off on Tristan.

Tristan da Cunha is such a small, beautiful, strange and lonely island. I was almost expecting to find a lost native tribe there, but in truth, it looked like any small town in England, with tiny gardens in front of their houses. Once we arrived at the island we had the choice between taking a touristic tour of the potato fields, where the Tristanians go in summer for holidays, or exploring the island independently.

I decided to go off to the north of the island. It was a perfect day, sunshine with no clouds in the sky, which was surprising for the South Atlantic. I wandered off past the remains of the famous 1961 eruption and the island’s own dumping place until I couldn’t go further. I arrived at a stony beach, from where I could see our ship, the M/S Merian, in the distance, anchored before the island’s coast, since our vessel was too big for Tristan’s small harbour.

I spotted the three penguins standing next to each other sun bathing. ‘Chilled guys’, I thought; and even when I drew closer to take the shot, they looked entirely relaxed and barely noticed me. It’s not like they had seen so many tourists around here! After taking the picture, I placed myself next to them (it’s surprising how smelly they are) to enjoy the view and the sun. Further down the beach, I also spotted a big mama seal and its adorable small fluffy baby. Right in front of me an orca emerged from the waters, properly trying to get to the seals. It flashed its fin before diving down again.

All in all, it was a surreal experience sitting on the remotest island on Earth surrounded by animals I usually only see in a zoo. After one wonderful day on Tristan da Cunha, we went back onboard to continue recovering the remaining OBS from the deep ocean.

By Maria Tsekhmistrenko, University of Oxford (UK)

References

SAMPLE webpage

ISOLDE project description

OBS provided by DEPAS pool in AWI

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/.

A better framework for disasters

A better framework for disasters

The end of the Northern hemisphere summer tends to be a good time to regroup from natural hazards, as the frequency and intensity of storms, as well as the incidence of wildfires, tends to trail off. At the time of writing, however, Hurricane Willa had just crashed into Mexico, while Typhoon Yutu has just hit the Northern Mariana Islands so hard that any equipment designed to record wind-speed had been swept away. Both storms rapidly strengthened, and the latter was described by the US National Weather Service as ‘likely [to] become the new yard stick by which future storms will be judged.’

Super Typhoon Yutu (24 October 2018) making its way towards the Northern Mariana Islands, a territory of the United States. (Photo: Joshua Stevens/NASA Earth Observatory)

What if we changed the way we think about such events, though? What if, instead of focusing on the wind-speed of a typhoon or the magnitude of an earthquake, the first points of discussion were about the human aspect and impact associated with a specific event. How would this summer’s events be framed? It’s a crucial distinction; natural disaster is in some ways a paradox in terms – although the hazard, or physical manifestation, of a hurricane or earthquake is natural, the impacts, and thus the disaster, are entirely a result of human exposure and vulnerability. Let’s first explore some of the most dramatic themes from this summer’s disasters, and then try and put them in this new human context.

What links this summer’s events?

The recent Hurricanes – Yutu, Willa, Florence and Michael – encapsulate well the intensity and frequency at which we’ve seen disasters come over the last few months. Earthquakes, storms, droughts and wildfires have all caused havoc in a hugely diverse spectrum of locations, and while the specter of natural hazards is always present in many parts of the world, there seems to be something more intense and urgent with respect to this summer’s catastrophes, especially in the media coverage.

The availability of smartphones and the proliferation of social media use means we can see ever more easily from the safety of our homes what others experience in terror during disasters; who could forget the scarring imagery from the earthquake and tsunami in Lombok in September, as houses were tossed about like toys as the ground turned to liquid.

Elsewhere, Japan experienced a plethora of hazards as flooding, typhoons, landslides, earthquakes and drought brought a whole range of challenging conditions which caused a large number of fatalities, despite Japan’s status as one of the best prepared countries in the world for natural hazards.

Much of the media discussion related to disasters has focused on the links between hazards and climate change, and whether the severity of events like Hurricane Florence can be attributed in part to anthropogenic emissions. While it has historically proven difficult to attribute the strength of different storms to climate change, this summer marked the first time scientists attempted it in earnest while an event was taking place – some researchers argued that the rainfall forecast for Hurricane Florence was 50% higher than it would otherwise have been, although such estimates are still in their infancy. What is clearer from scientific predictions of future climate change is that storms will likely be stronger, wetter and slower moving, suggesting similar intense storms could become more normal.

Beyond tropical storms, records were broken by other catastrophes. The Northern hemisphere wildfire season was among the worst we’ve ever experienced on record, at least in terms of acreage burned. Californian fires were so intense that smoke was noticeable on the East Coast, while the extent of fire in western Canada was second only to the cataclysmic fires last year. Abnormally warm temperatures in Scandinavia prompted wildfires to break out north of the Arctic circle, an extremely rare and concerning occurrence.

A different way to think about catastrophes

While it’s interesting and important to discuss the potential for increased storm severity as a result of climate change, it seems that this should only form a part of the larger discussion: how will trends in climate co-evolve with trends in human exposure and vulnerability to hazards? Similarly, why focus on the numbers associated with a disaster – the earthquake magnitude, the depth of flooding, acres of forest burned – when we could instead look at who has been impacted, and how to prevent this in the future.

It’s especially important to frame the ‘cost’ of a given event in this context. Often, we think of cost in either loss-of-life or financial terms, but it’s worth considering those as functions of exposure and vulnerability. For example, Hurricane Florence, which recently made landfall on the US eastern seaboard, is likely to cost  40-50 billion US dollars. Compare this to Hurricane Maria, which devastated Puerto Rico in 2017; some estimates for the cost of the storm were around 100 billion US dollars. While Hurricane Maria cost roughly twice as much as Florence, the relative impact on Puerto Rico was far greater than that value would imply. The vulnerability of the economy of Puerto Rico to a disaster of that scale was far higher than the mainland US; with a GDP of over 10 trillion US dollars, the US economy can absorb shocks like Florence, but the GDP of Puerto Rico declined by a massive 8% in the aftermath of Maria. It is worth noting that Puerto Rico is in fact a territory of the US, and received federal funding to assist with recovery – so the economic impact might even have been more severe without it.

U.S. Customs & Border Protection & FEMA personnel deliver food and water to isolated Puerto Rico residents after their bridge was destroyed by Hurricane Maria in the mountains around Utuado, Puerto Rico (Photo: U.S. Air Force/Master Sgt. Joshua L. DeMotts via FEMA)

We can build the same framing for loss of lives; countries with well-developed disaster response and recovery mechanisms suffer significantly fewer fatalities in the face of a similar magnitude event to a poorly equipped country, all things being equal. This kind of social vulnerability to disaster is difficult to quantify, and encompasses a range of aspects including cultural awareness of natural hazards and healthcare expenditure, but it has to be considered alongside the trends in hazard intensity.

I would argue that coverage of (and research related to) disasters needs to shift away from the headline numbers, like skyrocketing costs or the increasing intensity of storms and wildfires, and instead discuss whether disasters are hitting harder in places that are more vulnerable, or whether the relative economic or human exposure to a given type of disaster is worsening or not. While it’s fascinating to see images of multiple hurricanes over a single basin, it’s an incomplete picture unless the risk is incorporated.

Flash flood impacts in Peru after torrential rain in 2013 (Photo: Galeria del Ministerio de Defensa del Perú via Flickr)

Reframing our vision of disasters would put the focus squarely on where inequality and climate change interact; if more vulnerable developing countries or regions are expected to be more exposed to disasters under a changing climate, then there is real potential for inequalities to be exacerbated – and this is indeed what the UN anticipates will occur. More fundamentally, reframing would help us shift away from a coldly analytical perspective of ‘disasters by the numbers’ and instead consider where the worst impacts would be, and who the people at risk are. While trends in the developed world indicate fewer and fewer deaths from disasters over the last 100 years, many countries don’t have the same capacity to absorb shocks.

The human tendency to dwell on the extraordinary, and the ephemeral nature of modern news coverage certainly encourages reporting to focus on the records broken by a given event. Perhaps it’s futile to add another voice to the many that have already asked for more context and temperance from such coverage, but it seems important to highlight that there may be other ways to cover disasters; those affected may benefit greatly, in both the long and short term.

Robert Emberson is a Postdoctoral Fellow at NASA Goddard Space Flight Center, and a science writer when possible. He can be contacted either on Twitter (@RobertEmberson) or via his website (https://robertemberson.com/)

Editor’s note: This is a guest blog post that expresses the opinion of its author, whose views may differ from those of the European Geosciences Union. We hope the post can serve to generate discussion and a civilised debate amongst our readers.

Imaggeo on Mondays: Small scale processes, large scale landforms

Imaggeo on Mondays: Small scale processes, large scale landforms

This picture was taken in a sea cliff gully landscape at the Portuguese coast. It shows the microrelief which small scale wash and erosional processes produce in these poorly consolidated sediments. These small scale landforms could be interpreted as initial stages of larger scale gully landforms, which can be seen in the back. This highlights the importance of regarding scales and scale linkages in the geosciences.

Description by Jana Eichel, as it first appeared on imaggeo.egu.eu.

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/.