Could underwater sound waves be the key to early tsunami warnings?
MATHEMATICIANS have devised a way of calculating the size of a tsunami and its destructive force well in advance of it making landfall by measuring fast-moving underwater sound waves, opening up the possibility of a real-time early warning system.
The sound waves, known as acoustic gravity waves (AGWs), are naturally occurring and can be generated in the deep ocean after tsunami trigger events, such as underwater earthquakes.
They can travel over 10 times faster than tsunamis and spread out in all directions, regardless of the trajectory of the tsunami, making them easy to pick up using standard underwater hydrophones and an ideal source of information for early warning systems.
In a new study published in the Journal of Fluid Mechanics, scientists from Cardiff University have shown how the key characteristics of an earthquake, such as its location, duration, dimensions, orientation, and speed, can be determined when AGWs are detected by just a single hydrophone in the ocean.
More importantly, once the fault characteristics are found, calculating the tsunami amplitude and potential destructive force becomes more trivial, the researchers state.
Lead author of the study Dr Usama Kadri, from Cardiff University’s School of Mathematics, said: “By taking measurements of acoustic gravity waves, we basically have everything we need to set off a tsunami alarm.”
Underwater earthquakes are triggered by the movement of tectonic plates on the ocean floor and are the main cause of tsunamis.
Tsunamis are currently detected via dart buoys – floating devices that are able to measure pressure changes in the ocean caused by tsunamis. However, the technology relies on a tsunami physically reaching the dart buoys, which could be problematic if the buoys are close to the shoreline.
The current technology also requires the distribution of a huge number of buoys in oceans all around the world, which is very costly.
“Though we can currently measure earthquakes using seismic sensors, these do not tell us if tsunamis are likely to follow,” Dr Kadri continued.
“Using sound signals in the water, we can identify the characteristics of the earthquake fault, from which we can then calculate the characteristics of a tsunami. Since our solution is analytical, everything can be calculated in near real-time.
“Our aim is to be able to set off a tsunami alarm within a few minutes from recording the sound signals in a hydrophone station.”
AGWs are naturally occurring sounds waves that move through the deep ocean at the speed of sound and can travel thousands of metres below the surface.
AGWs can measure tens or even hundreds of kilometres in length and it is thought that certain lifeforms such as plankton, that are unable to swim against a current, rely on the waves to aid their movement, enhancing their ability to find food.
The Range’s Swansea Store Shortlisted for ‘Best Christmas Display’
Christmas has arrived early for The Range stores in Wales, boasting gigantic displays of all-things festive! The Range is well known for going all out during the Christmas season to create a fun and magical experience full of trees, lights, decorations and much more for their customers to enjoy and this year is no exception. The Range in Swansea surpassed expectations with a display so great, it’s left them shortlisted for ‘Best Christmas Display’ out of all The Range’s 182 stores.
Local coronavirus restrictions imposed to control outbreaks in South Wales
Coronavirus laws are being tightened in four more Welsh authorities – Blaenau Gwent, Bridgend, Merthyr Tydfil and Newport – following a sharp rise in cases, Health Minister Vaughan Gething today announced.
The new measures will come into force at 6pm on Tuesday 22 September 2020, to protect people’s health and control the spread of the virus in the four local authority areas.
The new restrictions will apply to everyone living in Blaenau Gwent, Bridgend, Merthyr Tydfil and Newport:
People will not be allowed to enter or leave these areas without a reasonable excuse, such as travel for work or education;
People will only be able to meet people they don’t live with outdoors for the time being. They will not be able to form, or be in, extended households;
All licensed premises will have to close at 11pm;
Everyone over 11 will be required to wear face coverings in indoor public areas – as is the case across Wales.
From 6pm on Tuesday 22 September, the requirement for all licensed premises to close at 11pm will also be extended to Caerphilly borough.
Health Minister, Vaughan Gething, said:
“Following the decision to place additional coronavirus restrictions in place in Caerphilly and Rhondda Cynon Taf, we have seen a worrying and rapid rise in cases in four other south Wales council areas – Blaenau Gwent, Bridgend, Merthyr Tydfil and Newport.
“In many cases, this is linked to people socialising indoors without social distancing. We are seeing evidence of coronavirus spreading. We need to take action to control and, ultimately, reduce its spread and protect people’s health.
“It’s always a difficult decision to introduce restrictions but coronavirus has not gone away – it is still circulating in communities across Wales and, as we are seeing in parts of South Wales, small clusters can quickly cause real issues in local communities.
“We need everyone’s help to bring coronavirus under control. We need everyone to pull together and to follow the measures which are there to protect you and your loved ones.”
The restrictions are being introduced following a rapid increase in the number of confirmed cases in coronavirus, which have been linked to people meeting indoors, not following social distancing guidelines and returning from summer holidays overseas.
The Welsh Government will call an urgent meeting of all local authority, health board and police forces from Bridgend to the English border tomorrow to discuss the wider situation in South Wales and whether further measures are needed across the region to protect people’s health.
The new local restrictions measures will be kept under regular review. They will be enforced by local authorities and by the police.
Keep Wales safe by:
Always keeping your distance
Washing your hands regularly
Working from home wherever you can
Following any local restrictions
Following the rules about meeting people
Staying at home if you or anyone in your extended household has symptoms.
Welsh legislation will restrict those travelling from hotspot areas
MARK Drakeford, First Minister of Wales, has today announced legislation which will restrict those coming from coronavirus hotspot’s from travelling to Wales.
The Prime Minister, Boris Johnson has refused to impose rules which prohibit those from areas where the infection rate is high from entering low virus rate areas’s.
Mr Drakeford has made two requests to the Prime Minister requesting to impose rules which will mean those from high virus areas in England be prohibited from travelling to Wales, a request which has been denied by Mr Johnson.
The powers set by Mr Drakeford will come into force by the end of the week, unless Boris Johnson takes action sooner.
Speaking at the Plenary today, Mr Drakeford made the announcement, stating if Mr Johnson does not reply to his request by Friday then The Welsh Government will bring in legislation to restrict travel from those in English lockdown areas travelling to Wales.
Mr Drakeford said this was not a case of all those from England being restricted travel to Wales, just hotspot areas.
He said: “Evidence from public health professionals suggests coronavirus is moving from east to west across the UK and across Wales. As a general rule, it is concentrating in urban areas and then spreading to more sparsely populated areas as a result of people travelling.
“Much of Wales in now subject to local restriction measures because levels of the virus have risen and people living in those areas are not able to travel beyond their county boundary without a reasonable excuse. This is designed to prevent the spread of infection within Wales and to other areas of the UK.
“We are preparing to take this action to prevent people who live in areas where there are higher Covid infection rates across the UK from travelling to Wales and bringing the virus with them.
“I am determined to keep Wales safe.”
The legislation, which is understood to come into force Friday, October 16 at 6pm, will mean those travelling to Wales from areas of England which are classed as virus hotspot’s will be restricted.
The new legislation also restricts those travelling into Wales from high virus prevalence areas from Northern Ireland and Scotland.
The Leader of the Opposition in the Welsh Parliament – Paul Davies MS – has rounded on the First Minister over a ban on people entering Wales from England, and the Labour Party’s inability or unwillingness to publish comprehensive data proving that transmission rates are accelerating due to travel.
Mr Davies took the First Minister to task during Plenary today (October 14), and referred to a statement made by the leader of the Labour Party on September 23 when he said that the Welsh Government was not seeing any spikes at all in infection due to travel and tourism.
Mr Davies said that the people of Wales deserve to have sight of the data that underpins the Welsh Labour-led Government’s position on this matter, so that they can be confident that the Government’s actions are proportionate to the threat of the virus in their area.
Mr Davies also referred to a paper that accompanied the First Minister’s letter to the Prime Minister yesterday, a paper – that was not peer-reviewed – that confirms the data “…does not constitute definitive proof” in favour of a travel ban.
Mr Davies said: “The First Minister and his Government have acted rashly and without examining a range of other factors before a conclusion on whether to impose a travel ban or not is reached, while at the same time seemingly ignoring the fact that transmission rates in relation to travel had already peaked in August and September.
“It is incumbent on the First Minister to explain just why he has chosen to act in this way, and what supporting evidence he and his Ministers have seen to justify a ban and then publish it so it can be properly scrutinised.
“If he cannot or will not, then he must review and rescind this ban immediately.”
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