Acoustic waves warn of tsunami

When a coastal area is about to be hit by the waves of a tsunami, time is everything. The earlier we know where and when it is going to hit the coast, the more chances there are to evacuate the area. Early warning systems play a crucial role. Until now, seismic signals were used to issue such warning. These are subsequently confirmed or cleared by measuring sea level height. This approach stems from the fact that shallow submarine earthquakes exceeding a given magnitude are the most likely causes of tsunamis.

More recently, an EU funded project called NEAREST found a better way of identifying a tsunami threat at early stage. “To do this we developed a new device we called tsunameter that we put as close as possible to those places where we know that is very likely a tsunami is generated”, says Francesco Chierici, who is the project coordinator and also works as a researcher the Radio Astronomy Institute (IRA), in Bologna, Italy. This tsunameter can be placed close to the geological faults that are responsible for the earthquake and, accordingly, for tsunamis. Detecting a tsunami near its source is crucial “expecially in peculiar environments such as the Mediterranean where the tsunami are generated very close to the coasts”, says Chierici.

Every device is connected with a surface buoy and consists of a set of instruments collecting several kinds of data. These include local acceleration and pressure of water, seismic waves, and, in particular, the acoustic waves generated by tsunamis. With this information, actual tsunamis can be distinguished from the background noise, “using a specific mathematical algorithm” which is interpreting the data. Under the project, the tsunameter had been tested for a year off the Gulf of Cadiz in Spain, at water depth of 3,200 metres. Since the project was completed, in March 2010, the tsunameters are now tested in a new research programme called Multidisciplinary Oceanic Information SysTem (MOIST), run by the Italian National Institute of Geophysics and Vulcanology (INGV) in Rome.

The idea of using acoustic waves as tsunami signal is effective, according to Stefano Tinti, professor of geology at the University of Bologna, Italy, and an expert in tsunamis. “Their speed of propagation is slower than that of seismic waves, but still quicker than that of the tsunami,” he tells youris.com. The problem is the technology “is still in an experimental stage and it’s not so easy to separate the hydroacoustic signal from the others when the detector is so close to the source.”

Another issue is the cost of installation and maintenance. “Off-shore detection systems are more expensive than coastal ones,” he adds. Tinti also believes it could be more effective to use the many islands spread around the Mediterranean. “The detection could be of no use in terms of warning system for the very point where the detection takes place,” he contends, “but it is still very useful for other areas of the coast.” The difficulties related to having a costly off-shore observation system are confirmed by Fernando Carrilho of the Portuguese Marine and Atmosphere Institute (IPMA), which was a project partner. When the Portuguese government decided to build a national tsunami early warning system, he explains, experts opted for a cheaper coastal sea-level observation system.

Other experts point out to issues related to providing a timely warning to the population. “Measurements would need to be far enough from the land to be affected to give enough time to raise the alarm,” says Philippe Blondel, acoustic remote sensing expert at the department of physics of the University of Bath, UK. Apart from which early warning system you choose, the difference between saving lives or not is preparedness. “For example, if the Vesuvius erupts and a flank collapses into the sea, this would affect the millions of people in and around Naples, in Italy. Even with the best organisation, there are only so many roads available for people to get away in a hurry,” says Blondel.

A different level of preparedness is required in the Mediterranean, compared to the situation in Japan and United States where “as soon as a tsunami is confirmed as being underway, alarms will sound in all communities likely to be affected,” Blondel explains.  Clear evacuation routes have been signposted, he believes, and everybody has been trained to know where to go. He quotes the example of the US West coast, where many long, romantic sandy beaches now have signs every few hundred meters saying ‘tsunami risk: run this way’ in clearly understandable icons.

Antonio Bombelli: Africa’s carbon cycle under scrutiny

The results of climate change are going to have more impact in Africa than other regions due both to ecological and socio-economic factors. However, little is known about the role of Africa with regard to greenhouse gases emissions. Antonio Bombelli of the Euro-Mediterranean Centre on Climate Change, headquatered in Lecce, Italy, has been the project manager of the first research project that built a greenhouse gasses monitoring network in Sub-Saharan Africa. The project, CARBOAFRICA, completed in 2010, was designed to respond to a specific interest at European level in better understanding carbon cycle in that area. Bombelli tells youris.com about progress in Sub-Saharan African since the project was completed.

What are the main achievements of the project?
There has been different kind of achievements. The first, and maybe the most important, is that we succeeded in building and coordinating a monitoring network for greenhouse gases in Sub-Saharan Africa. Before the beginning of the project there were just a few monitoring stations and their measures were not integrated. The network was a specific request from the European Commission, but it was obvious that we could make it happen. At the end we had 19 stations in 11 different countries. Moreover, in Ghana we built the first carbon monitoring station within a forest in Africa. That has been important to better understand how a forest actually works as a carbon sink.

Have many problems arisen during the course of the project?
There have been different problems at different levels. To start a project in Africa you have to develop a good partnership with the right local institutions. This takes time and may causes delays in the early stages. Then, there are practical problems. For instance, the same instrumentation that works efficiently in temperate countries, like European ones, can have big problems in the extremely hot or humid conditions you can find in Africa. Moreover, often in the African context you cannot just apply the same research protocols and modelling approaches used for other regions.

What can we say about the role of Sub-Saharan Africa in relation to greenhouse gases emissions?
We already suspected from previous researches that Africa as a continent could be a net sink. It means that on average African ecosystems absorb more carbon than they release. The project confirmed our suspicion, but we cannot be 100% sure because the network was not wide enough to extend our results at a continental level with the required reliability. On this point, I think we would need more data coming from continuous measurements. Unfortunately today, after a couple of years since the project ended, many of the monitoring stations have been closed down because of lack of resources.

We tend to think that greenhouse gases emissions are a Western problem. Why is it important to study this subject in Africa?
First, it is important because we know very little about this kind of topics on Africa, especially Sub-Saharan region. Second, because if we really want to understand the global CO2 balance we cannot forget Africa. At the moment, with some exceptions like the Republic of South Africa, African countries are not important emitters, but they are among the most vulnerable to climate change.

Have these findings been beneficial for further research?
There has not been a proper follow up, because part of the network is not working any more. But the field data we collected have been used as a confirmation of greenhouse gases emission estimated from satellite information. And they are now used in another EU funded project called CLIMAFRICA. The latter is centred on making climate change previsions and assessing its impacts on the availability of natural resources and the evaluation of the vulnerability of ecosystems.

Originally on Youris.com on 2nd of August 2013.

Local input key in multi-risk planning decisions

Land use planning and management now has all the scientific tools required for decisions making. But scientists have yet to have an opportunity to collaborate with local authorities to implement them.

Landslides and floods are increasingly occurring natural events. They continue to damage infrastructures and farmland across the EU. Meanwhile, they are also putting people’s life at risk. The problem is that policy makers do not always take into account the available scientific knowledge on the subject of land use planning and management. They do not fully exploit existing scientific models, which are crucial to mitigate the effects of these calamities in the future.

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More than water play

Water policy instruments based on evidence-based and environmentally sound economic measures should replace financial instruments merely designed to recoup water costs.

Jaroslav Mysiak is a senior researcher in environmental economics at the Fondazione Eni Erico Mattei and theEuro-Mediterranean Center for Climate Change, both in Venice, Italy. As the co-ordinator of the EPI-WATERproject, he is talking to youris.com about assessing effectiveness and efficiency of economic policy instruments to assist in meeting EU water policy goals of increasing environmental protection of water resources.

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Age-proof diet for longevity

We are what we eat. However, little is known on how a specific dietary regime can impact the life of the elderly. Now, researchers from an EU funded project called NU-AGE are investigating the effects of the Mediterranean diet on older people. Their aim is to get clues on how to counteract physical and cognitive decline through diet changes.

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