Times of Oman
Aug 29, 2015 LAST UPDATED AT 11:35 AM GMT
Scientists search rubbish on Oman's beaches for clues to cyclones
August 20, 2014 | 12:00 AM
Based on the dates on plastic food and drink labels, it was determined that the litter had been carried to the beach during Cyclone Gonu in 2007 and Cyclone Phet in 2010. Photo supplied

Muscat: Scientists from GUtech found a silver lining in the unsightly litter on Oman's beaches when they realised it could provide useful information about past cyclones that have struck the coast.

Dr Goesta Hoffmann and Dr Klaus Reicherter have just published a paper on their findings and shared their work with Times of Oman.

Dr Klaus Reicherter

The two professors from GUtech's Department of Applied Geosciences were doing field work in Ras Al Hadd when some of their students came across rubbish that was arranged in wrack lines, or lines of debris left by high tides, on the beach.

"We realised it must have been from some kind of flooding. The students then realised that it was all floatable and one of them suggested we look for production and expiry dates. We did this for the rest of the day and successfully dated these two wrack lines this way," Hoffmann told Times of Oman.

Dr Goesta Hoffmann

They were careful to differentiate between litter in the wrack line deposits from any potentially newer waste.

The litter from the flooding was mixed with sediment and natural waste and partially buried, too. Based on the dates on plastic food and drink labels, pop cans, and even a number of Mountain Dew bottles, they were able to determine that the litter had been carried high up onto the beach during Cyclone Gonu in 2007 and Cyclone Phet in 2010. "Many of the dates were quite similar and that allowed us in the end to narrow down the timing and confirm that one was from Gonu and the other was from Phet," Hoffmann explained.

By measuring the location of the wrack lines they were able to find out the maximum flooding height from these cyclones, information which could be useful for an early warning system for future storms, tsunamis and other big weather events. The information can be adapted for modelling and creating future 'what if' scenarios, Hoffmann said.

"Measurements are of course better then these observations. But if you do not have them and want to define worst-case scenarios, this method is quite useful. In the end some people model the impact of future events. These models need to be validated. Our litter deposits are a very good way to calibrate these models," explained Hoffmann.

Hoffmann says that this approach is highly accurate in terms of dating the deposit, but, the older the deposit, the more likely the relevant information will be lost. However, considering that a lot of rubbish, such as plastic and glass, has a lifespan of millions of years, the production dates can last a very long time.

In Oman litter is quite new, so it would be difficult to date weather events are from or before 1970, but in other countries this research method could prove useful. For earlier cyclones and other extreme wave events other deposits such as sediments and rocks left behind could be studied instead, Hoffmann said.

Using litter found in wrack lines to assess the effects of weather events works well in coastal areas that aren't widely used by people, he added. Many beaches, such as those around Muscat, are cleaned on a regular basis so the litter is removed, but elsewhere it can provide valid information as long as the material stays in the wrack lines. It can be found and analysed for the dates it carries. "My Omani colleagues who read the paper pointed out that obviously Mountain Dew is a very useful drink to have, since the bottles are so abundant here," he concluded with a laugh.

To get in touch with the reporter sarah@timesofoman.com

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