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Top ten tourist beaches threatened by tsunamis

Top ten tourist beaches threatened by tsunamis

December 2004 saw one of the deadliest natural disasters in recorded history. 228,000 people were killed when an earthquake off the coast of the Indonesian island of Sumatra triggered tsunami waves up to 30 m high. The destruction was extreme as the waves hit 14 different countries around the Indian Ocean. Economic losses totalled over 10 billion US dollars. The tourism industry in particular suffered a significant blow. In Phuket, a province of Thailand, a quarter of the island’s hotels had closed six months after the tsumani.

“The 2004 Sumatra tsunami and some of the recent Pacific Island tsunamis have shown their devastating impact on beaches and beach-related tourism,” says Andreas Schaefer, a researcher from the Karlsruhe Institute of Technology (KIT). But where is disaster likely to strike next? And can we be prepared for it?

Schaefer and his colleagues are trying to find out. “We asked the question: can we quantify potential tsunami losses to tourism industries along beaches?” he says. The number of tourists visiting the most exotic locations in the world, places such as Thailand, Indonesia, Colombia and Costa Rica, are rising twice as fast as the global average. In some cases, visitor numbers are growing by as much as 11 percent each year.

This rise in tourism in tsunami-prone locations is potentially a cause for real concern. “We compiled the first ever global loss index for the tourism industry [associated with beaches],” continues Schaefer. His findings were presented last month at the European Geosciences Union General Assembly in Vienna .

Beaches can be affected by tsunamis in a variety of ways. As well as the immediate threat to human life, a tsunami wave can leave behind piles of debris or offshore sand that can damage a beach environment. Alternatively, large swathes of beach sand might be removed by erosion. And in cases where an earthquake is very close to the shore, the beach itself may be down-thrust or uplifted during the event, leaving it either permanently submerged underwater or high and dry.

To quantify the locations in the world that are most at risk, Schaefer and his colleagues used two large datasets: tourist information and earthquake statistics.

Tourism-derived GDP per capita across the world. (Image credit: Andreas Schaefer)

To calculate the human exposure, “we compiled a global tourism destination database,” he explains. This database includes over 200 countries, at least 10,000 tourist destinations, more than 24,000 beaches, and almost a million hotels from all around the globe.

“It was important to get the latest and best tourism and hotel information,” says James Daniell, another member of the KIT research team. “Tourism contributes over 6 trillion [US] dollars directly and indirectly to the global economy every year.”

The research team then calculated tsunami probabilities all around the world using earthquake statistics and tectonic modelling. Chile, central America, Indonesia and Japan are the main countries that frequently experience large tsunamis.

Over longer time periods, the Caribbean and Mediterranean are also likely to be affected by rarer events. To put the numbers in perspective, if you spend a day on the coast of Mexico you have a one in 60,000 chance of seeing a tsunami; in Crete, this decreases to one in 600,000.

To model the tsunamis, it is also important to have a good understanding of the shape of the seafloor in the vicinity of the tourist sites. In the deep ocean, big tsunamis can have gaps between waves of as much as 200 km and wave heights as small as 1 m; ships are often unable to feel them passing. But as they approach the shore, the water shallows, causing the waves to slow down and pile up. The wave spacing decreases to less than 20 km, whilst the wave heights can grow to tens of metres. Hence, what looks like an innocuous fluctuation at sea can cause major damage when it reaches land. The depth of the adjacent seafloor plays a major role in this.

Simulated tsunamis across the world showing maximum potential wave heights. (Image credit: Andreas Schaefer)

Given the large number of variables at play, tsunami modelling involves many calculations and typically requires the use of a supercomputer. But in a paper published last year, Schaefer helped to develop a new simulation framework called TsuPy, which allows for quick modelling of tsunamis on personal computers. With this in place, he could rapidly simulate more than 10,000 tsunamis all around the world, calculate the expected wave heights at the tourist sites in his database, and estimate the likely economic losses.

The researchers estimate 250 million US dollars in global annual loss to the tourism industry from tsunami waves. Furthermore, every 10 years they expect a single $1 billion event.

Of all the tourist destinations, “Hawaii is the number one,” says Schaefer. This is “because of all the potential tsunamis that come from around the Pacific Ring of Fire,” he explains. “There are so many [tsunami] sources all around, that, even though they are far away, they have an effect.”

The last major tsunami to strike Hawaii was as a result of the biggest earthquake ever recorded: the 1960 magnitude 9.6 Valdivia earthquake on the coast of Chile. 60 people on Hawaii were killed and the damage amounted to 500 million US dollars in today’s terms.

Top ten locations on the global risk index for beach tourist destinations threatened by tsunamis. (Image credit: Andreas Schaefer)

Other notable locations on the top ten list include Valparaiso (Chile), Bali (Indonesia), and Phuket (Thailand). “Locations that are known for their tourism are at the top of the list because there is a lot [of existing infrastructure] that could be damaged,” explains Schaefer.

Slightly surprisingly, southwest Turkey is also high on the list. Furthermore, places like Tonga and Vanuatu are particularly at risk. They have rapidly developing tourist industries and large projected losses per dollar of tourism-related business, so they feature highly on Schaefer’s list. “They are mostly small island nations with a significant need for tourist dollars,” explains Daniell.

For many parts of the world, the results are not necessarily good news. But they are a first step inasmuch as they highlight the locations that are currently thought to be at greatest risk. “We hope, with these results, to raise awareness among tourists. But they do not need to be afraid,” says Schaefer. With adequate preparation and evacuation planning, it is hoped that future disaster on the scale of the 2004 event might be averted.

By Tim Middleton, EGU 2018 General Assembly Press Assistant

References

Schaefer, A., Daniell, J., and Wenzel, F. Beach Tsunami Risk Modelling – A probabilistic assessment of tsunami risk for the world’s most prominent beaches. Geophysical Research Abstracts, Vol. 20, EGU2018-11955, 2018, EGU General Assembly 2018 (conference abstract)

Schaefer, A. and Wenzel, F. TsuPy: Computational robustness in Tsunami hazard modelling. Computers & Geosciences, 102, 148-157, 2017

April GeoRoundUp: the best of the Earth sciences from the 2018 General Assembly

April GeoRoundUp: the best of the Earth sciences from the 2018 General Assembly

The 2018 General Assembly took place in Vienna last month, drawing more than 15,000 participants from 106 countries. This month’s GeoRoundUp will focus on some of the unique and interesting stories that came out of research presented at the Assembly.

Mystery solved

The World War II battleship Tirpitz was the largest vessel in the German navy, stationed primarily off the Norwegian coastline as a foreboding threat to Allied armies. The ship was 250 metres in length and capable of carrying around 2,500 crewmates.

Despite its massive size, the vessel’s presence often went unnoticed as it moved between fjords, masked by a chemical fog of chlorosulphuric acid released by the Nazi army.

Ultimately the ship sank and the war ended, but evidence of the toxic smog still lingers today, in the tree rings of Norway’s nearby forests.

Claudia Hartl, a dendrochronologist from the Johannes Gutenberg University in Mainz, Germany, made this discovery unexpectedly while sampling pines and birches near the Norwegian village Kåfjord. She and her research team presented their findings at the General Assembly in Vienna last month.

The German battleship Tirpitz partly covered by a smokescreen at Kaafjord. (Image Credit: Imperial War Museums )

Hartl had been examining wood cores to draw a more complete picture of past climate in the region when she noticed that some trees completely lacked rings dating to 1945,” reported Julissa Treviño in Smithsonian Magazine.

The discovery was odd since it is rare for trees to have completely absent rings in their trunks. Tree ring growth can be stunted by extreme cold or insect infestation, but neither case is severe enough to explain the missing tree rings from that time period.

“A colleague suggested it could have something to do with the Tirpitz, which was anchored the previous year at Kåfjord where it was attacked by Allied bombers,” explains Jonathan Amos from BBC News.

The researchers indeed found physical and chemical evidence of the smokescreen damage on the trees, demonstrating the long-lasting impact warfare can impart onto the environment.

 

What you might have missed

Seismicity of city life

Researchers use seismometers to record Earth’s quakes and tremors, but some seismologists have employed these instruments for a different purpose, to show how humans make cities shake. “This new field of urban seismology aims to detect the vibrations caused by road traffic, subway trains, and even cultural activities,” reports EGU General Assembly Press Assistant Tim Middleton on GeoLog.

With seismometers, Jordi Díaz and colleagues at the Institute of Earth Sciences Jaume Almera in Barcelona, Spain have been able to pick up the seismic signals of major football games and rock concerts, like footballer Lionel Messi’s winning goal against Paris Saint-Germain and Bruce Springsteen’s Barcelona show.

Seismic record captured by the seismometer during the Bruce Springsteen concert. The upper panel shows the seismogram, while the lower panel shows the spectrogram where it is possible to see the distribution of the energy between the different frequencies. (Image Credit: Jordi Díaz)

Díaz’s project first began as an outreach campaign, to teach the general public about seismometers, but now he and his colleagues are exploring other applications. For example, the data could help civil engineers with tracking traffic and monitoring how buildings withstand human-induced tremors.

Antarctica seeing more snow

Meanwhile in Antarctica, snowfall has increased by 10 percent in the last 200 years, according to new research presented at the meeting. After analysing 79 ice cores, a research team led by Liz Thomas from the British Antarctic Survey discovered that Antarctica’s increased snowfall since 1800 was equivalent to 544 trillion pounds of water, about twice the volume of the Dead Sea.

It has been predicted that snowfall increase would be a consequence of global warming, since a warmer atmosphere can hold more moisture, thus resulting in more precipitation. However, these ice core observations reveal this effect has already been happening. The new finding implies that Earth’s sea level has risen slightly less than it would have otherwise, but only by about a fifth of a milimetre. Though overall, this snowfall increase is not nearly enough to offset Earth’s increased ice loss.

Ocean’s tides create a magnetic field

Also at the Assembly, scientists presented new data collected from a team of ESA satellites known as Swarm, In particular, the satellite observations recently mapped magnetic signals induced by Earth’s ocean tides. As the planet’s tides ebb and flow, drawn by the Moon’s gravitational pull, the salty water generates electric currents. And these currents create a tiny magnetic field, around 20,000 times weaker than the global magnetic field.

Scientists involved with the Swarm project say the magnetic view provides new insight into Earth’s ocean flow and magnetic field, can improve our understanding of climate change, and help researchers build better Earth system models.

When salty ocean water flows through Earth’s magnetic field, an electric current is generated, and this in turn induces a magnetic signal. (Credit: ESA/Planetary Visions)

 

Other noteworthy stories:

 

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At the Assembly 2018: Friday highlights

At the Assembly 2018: Friday highlights

The conference is coming to a close and there’s still an abundance of great sessions to attend! Here’s our guide to getting the most out of the conference on its final day. Boost this information with features from EGU Today, the daily newsletter of the General Assembly – pick up a paper copy at the ACV entrance or download it here.

Union Sessions

The final day of the conference kicks off with the last Union session, Scientific research in a changing European Union (EU): where we stand and what we aim for (US5). Panelists will explore some of the challenges and potential threats to academics in the EU and how these issues can be addressed and overcome. The session will also outline some of the advantages of the EU, funding programmes that are currently provided and how the European Union can continue to develop and nurture its researchers.

Medal Lectures

Be sure to also attend the last two medal lectures of the assembly:

Short Courses

The last leg of short courses offers insight into new technologies, tips for publishing your work, and advice on how to develop your career. Here are a few of the short courses you can check out today:

Scientific Sessions

The three final interdisciplinary events also take place today. Early in the morning a series of talks will discuss biogeomorphology: conceptualising and quantifying processes, rates and feedbacks. Another session will explore medical geology, an emerging field of science that is dealing with the impact of natural geological factors, process and material on humans and animals health. Our final interdisciplinary event will explore sea-level changes from minutes to millennia, highlighting proxy records for constraining our understanding of present and future sea-level change

It’s your last chance to make the most of the networking opportunities at the General Assembly, so get on down to the poster halls and strike up a conversation. If you’re in the queue for coffee, find out what the person ahead is investigating – you never know when you might start building the next exciting collaboration! Here are some of today’s scientific highlights:

Today we also announce the results of the EGU Photo Contest! Head over to the EGU Booth at 12:15 to find out who the winners are.

What have you thought of the Assembly this week? Let us know at www.egu2018.eu/feedback and help make EGU 2019 even better.

We hope you’ve had a wonderful week and look forward to seeing you in 2019! Join us on this adventure in Vienna next year, 7–12 April 2019.

At the Assembly 2018: Thursday Highlights

At the Assembly 2018: Thursday Highlights

Welcome to the fourth day of General Assembly excitement! Once again the day is packed with great events for you to attend and here are just some of the sessions on offer. You can find out more about what’s on in EGU Today, the daily newsletter of the General Assembly – grab a copy on your way in or download it here.

Union-wide sessions

The Union-wide session of the day focuses on the Cassini mission to Saturn and future perspectives for the exploration of the outer solar system (US3). The session will feature reports on the amazing discoveries that this mission brought and the new understanding we have gained of the Saturnian system. Join the discussion from 8:30 to 12:00 in room E1.

Thursday’s Great Debate will discuss natural versus anthropogenic threats for life on Earth (GDB5 from 13:30-15:00 in room E1). The session will explore the consequences of extreme events, from magnetic field reversal to anthropogenic climate change, for life on Earth. Tune into to the sessions on Twitter using the #EGU18GDB hashtag or online by webstreaming.

The EGU Early Career Scientists’ Forum (12:15–13:15 in room N2) is the best place to find out more about the Union and how to get involved. Because the EGU is a bottom up organisation, we are keen to hear your suggestions on how to make ECS related activities even better. There will be plenty of opportunities during the forum for you to provide feedback. It’s also over lunch, so you’ll find a buffet of sandwiches and soft drinks when you arrive!

At the Early Career Scientists’ Forum you can let us know what you would like from the EGU, find out how you can get involved in the Assembly and meet other scientists in the EGU early career scientist community. (Credit: EGU)

Scientific Sessions

Some of today’s interdisciplinary highlights include sessions on…

Short Courses

Take the opportunity to expand your skills in one of today’s short courses and splinter meetings. Be sure to share what you learn on social media using the hashtag #EGU18SC:

Medal Lectures

There’s also a number of Medal Lectures on throughout the day – here’s a sample of what’s on offer:

If you need a change of pace, stop by the Imaggeo Photo Exhibition beside the EGU Booth (Hall X2, basement, Brown Level). You can vote for your favourite finalists there, but be quick because the voting deadline is today at midnight! While you’re in the area, you can also take the opportunity to meet your Division’s representatives in today’s Meet EGU appointments.

The Arts at EGU

Tonight from 19:00 to 20:00 in room E1 you can experience geoscience through music with a concert by EMusic (ElectroMagnetic Music), a collaboration between geophysicist Antonio Menghini and musician Stefano Pontani. Their new show “Sounds from the Geology of Italy”, will feature musical styling drawn from electromagnetic data collected in 4 beautiful scenarios: the Phlegrean Fields, Venice Lagoon, Selinunte Temple and Castelluccio Plain.

EGU’s poet (Sam Illingworth) and cartoonist (Matthew Partridge) in residence have been circulating the Assembly to share their conference experiences and communicate science. You can see their work posted daily here.

Have a lovely day!

The EGU General Assembly is taking place in Vienna, Austria from 8 to 13 April. Check out the full session programme on the General Assembly website and follow the Assembly’s online conversation on Twitter at #EGU18.