Mother nature's fury - are we safe from it?

Felt the tremor on the 30th Sept 2009 and was shocked at the extent of the earthquake as I am just living on the 6th floor. I realised that it was a 7.6 earthquake from Padang, Indonesia.

One cannot help but think about how natural disasters might affect Singapore. I suddenly recalled the following article on natural disaster - a special edition for Earth Day written by Keith Emuang:

MOTHER NATURE'S FURY
Singapore's geographical location has spared us from many natural disasters. In this special Earth Day (March 20) report, we ask why is this so? By KEITH EMUANG.


Living on an island, it is only natural for us to occasionally wonder how susceptible we are to natural occurring events like earthquakes, tsunamis and rising sea levels. Factors such as the lack of open spaces and highlands, and high density and high-rise dwelling, also fuel our concern.
The good news is that, based on recorded history, Singapore in a geological sense, has been spared from earthquakes and tsunamis. That is however, not to say that we are totally safe or completely free from any type of natural or climatic conditions.


EARTHQUAKE POSSIBILITY?

Studying an earthquake in the hope of anticipating one, involves the tedious seismological monitoring of complex tectonic plate behaviour. Presently though, even with sophisticated scientific land-based and satellite equipment, geologists remain unable to pinpoint the time, place and magnitude of an impending earthquake.

Singapore's susceptibility to an earthquake depends on the characteristics of the outermost layer of the earth's crust (lithosphere). This rigid layer is composed of sections called plates that are in constant motion, gliding on the top of the softer rock below. When two plates come together or collide, there is a tremendous stress and strain where they meet, and a boundary is formed. If the stress exceeds the elasticity threshold of the rocks, the plates can rupture, releasing an enormous amount of strain energy (an earthquake).

The subsequent release of seismic waves, heat and sound energy depicts the magnitude or strength of the earthquake. The area above and around this release of energy is usually most affected by the quake. If a landmass is above or near the boundary, tremors will be felt and if the quake is large enough and below water, a tsunami develops.

Fortunately Singapore does not lie on, along or in close proximity to any boundary. We are sandwiched by the Java trench in the west and south, and the Philippine Plate and trench in the east. We lie on the southerly extension of the Eurasian Plate, in what geologistsrefer to as a seismically stable zone, i.e. free from earthquakes.

According to the National Environment Agency (NEA), past data indicates that we have not suffered an earthquake nor been severely affected from any that have occurred in the region. And although tremors have been occasionally felt by high-rise dwellers in specific areas in Singapore, they are fairly weak. Associate Professor of Geography, National University of Singapore, Victor Savage, qualifies,"Although we are fairly safe, we have to recognise that many times, whenever there is a significant earthquake or volcanic eruption in Sumatra, we have felt the underground tremors in some parts of Singapore. This shows that we are not totally safe or removed from the tectonic instability that takes place in Sumatra."
In the interest of the public, the Meteorological Services Division of the NEA has set up a network of seismic sensors around the island to monitor the effects of these earthquakes from western Sumatra. The data is made available to engineers and researchers, while the general public can access this information whenever a tremor incident occurs on the island.


TSUNAMI LIKELIHOOD?
The 2004 Boxing Day Tsunami is one example of what can happen, in a regional sense, should the Indo-Australian and Burma (part of the larger Eurasian Plate) Plates meet. The boundary between these plates had slipped below sea level and the ensuing earthquake 'kicked up' or displaced hundreds of cubic kilometres of water. This generated a massive sea surge or tsunami, which in this particular instance, fanned out across the Indian Ocean.

As is the case with most tsunamis, the up to 700km/h wave speeds drops considerably before reaching coastlines. However, the size and height of the wave can swell enormously upon hitting land. The surging seas can inundate or flood coastal areas and communities lining the ocean, not unlike how the waters of the Indian Ocean had wrecked havoc across many countries sharing its waters.

The Boxing Day killer tsunami had lost much of its energy by the time it reached our shores. The main thrust of these waves was absorbed by the Sumatran landmass. So, in order to reach Singapore, it had to travel down the bottleneck that is the Malacca Straits. That took much of the sting out of the approaching waves. If a similar-type tsunami were to be triggered by an earthquake due to any boundary along the Indo-Australia Plate, we would be protected in a similar way.

The NEA feels that earthquakes in the region are most likely to occur along major fault lines off the outer coasts of Sumatra, Java and the Philippines. Being sheltered by the Indonesia Archipelago in the west and south and the Philippines in the east, it is very unlikely for Singapore to be directly affected by a tsunami.

Associate Professor Savage adds, "The South China Sea is nowhere as deep as the waters in the Indian or PacificOceans. Thus any tsunami generated from violent undersea disturbances such as massive earthquakes, volcanic eruptions or sub-marine landslides from the eastern areas of the region e.g. the Philippines and Japan, is unlikely to achieve great wave speeds or heights. Therefore any impact on Singapore is likely to be diffused, moderated and less damaging.

Backing this theory, former Geography Professor and author, Ooi Jin Bee, wrote in his article Earthquakes: Will They Hit Singapore? "The Krakatoa volcanic eruption of 1883, for example, generated a tsunami 40 metres high which penetrated 11km inland and totally or partially destroyed over 300 settlements along the Sumatran and Java coasts. Its effect on Singapore was, however, negligible.

HAZARDS THAT HIT HOME
Although we are fairly safe, we have to recognise that many times, whenever there is a significant earthquake or volcanic eruption in Sumatra, we have felt the underground tremors in some parts of Singapore.


We can only hope that our geographical location continues to offer us a haven from natural disasters. Also, we cannot afford to slip too deep into our comfort zone because there are still some climatic hazards, perhaps not as catastrophic but nonetheless, events we need to be aware of.

Few of us need reminding how bush fires in Singapore can seriously affect the air conditions here. During the hot season in Jan-Feb this year, it was reported at one stage that as many as six fires a day were breaking out across the island. Air quality was affected in many parts as a result of that. Smoky haze can also come about from forest fires in Sumatra or spewing volcanic ash such as Mount Pinatubo's cataclysmic eruption in 1991. Depending on their intensities and the direction of the winds, Singapore can be affected.

As recently as 1997, the Pollution Standard Index (PSI) had hit an all-time high of 226 (a reading above 100 being unhealthy). Then, raging Sumatran forest fires were to blame and it also proved what a public and health nuisance it can be.

Rising global temperatures due to an accumulation of greenhouse gases tends to worsen the problem. In the past 10 years, our planet has experienced the warmest climate on record with some of the hottest occurring between 1998 and 2004. Dry seasons become hotter and inevitably, the bush fires will increase in response.


These increasing global temperatures have also triggered the meltdown of our ice caps and the gradual peeling away of huge glaciers from the Arctic and Antarctic, thus raising the mean sea level. Experts belief that by 2100, there would be an estimated rise of between 10cm and 90cm in global sea levels.

Associate Professor Wong PohPoh, Department of Geography, National University of Singapore says, "The scientific community at large acknowledges that over the last 200 years, man has contributed much to the climate change or the phenomenon of global warming due mainly to the burning of fossil fuels.

While the impact of a sea level rise on Singapore is unlikely to be severe, areas with low-lying coasts can nonetheless be affected to some extent.

Professor Wong whose area of expertise lies in coasts and beaches, recounts an instance in December 1999 of how extreme high tides moved inland over the East CoastPark (near the Costa Sands Resort). "The seawater flooded the walkways in the front of the resort and stood up to the level of the stone benches and dustbins. Although this is merely a short-term event, it provides a good analogy for what might happen in the long term. This really shows our vulnerability.

MONSOON MAYHEM
As we are also prone to spells of incessant monsoon rains, flooding can and has been a problem. Granted that much has been and continues to be done to drain the heavy rains and waters from high tides, some parts of the island still remain prone to flooding. We only have to look back to as recently as March last year to realise what three days of persistent rains can still cause.


To alleviate the flooding problem, the Public Utilities Board has embarked on an ambitious project to build a barrage across the 350m-wide Marina Channel. This barrage will act as a tidal barrier to keep high tides at bay and also prevent low-lying areas in the city from flooding, especially when heavy rains coincide with high tides.

When completed in 2007, this will also dam up the MarinaBasin to create a reservoir that will turn seawater to freshwater and add to our water supply.

The close proximity to the Equator has provided Singapore with a tropical climate. However, the characteristic hot and humid weather conditions promote the development of lightning-producing thunderclouds. Based on figures posted on the NEA's website, Singapore experiences an average of 171 thunderstorm days annually. The lightning activity is also high. In fact, Singapore is one of the most lightning prone areas in the world.

Although most times lightning strikes the ground harmlessly, its destructive power is enormous. It can ignite forest fires, destroy trees, damage electronic equipment and disrupt electrical power and telecommunication systems. It is also a hazard to humans.

Most lightning deaths in Singapore occur in the months of April and November, coinciding with the heaviest thunderstorm months. The victims were often in open areas such as the sea, beaches or football fields. For deaths in sheltered areas, victims were often found under a hut, a shed or tree.

Between 2000-2003, lightning fatalities in Singapore averaged 0.35 deaths per million population. The authorities have done a lot to ensure that buildings, highways and other critical infrastructure, is protected from lightning strikes. The rest really depends on the precautions one takes, and Mother Nature.

ABOUT EARTH DAY
Singapore will be observing Earth Day on March 20.
The first Earth Day was officially observed in San Francisco on March 21 1970. The day was chosen to coincide with the Vernal Equinox, the moment when night and day are equal throughout the Earth.


This was symbolic and helped to remind of the Earth's wondrous system of balance, one that mankind is responsible for partially disrupting. It serves as a reminder for us to work to restore it.

Today, Earth Day is observed across the world in a variety of ways including events such as Car-Free Day, Tree-Planting Day, Beach Clean-Up Day, etc. It is a day to celebrate the wonders of our planet and re-instil the important need to care for and protect our natural environment not only for the present generation to enjoy but also for many generations to come.

GLOSSARY OF TERMS
* Vernal Equinox - spring Equinox around March 20
* Tectonic - the earth's crust and what happens within it
* Seismic - earthquakes and other vibrations of the earth
* Submarine landslides - underwater landslides
* Glaciers - slow moving rivers of compacted ice coming down mountains


GO GREEN TO CELEBRATE EARTH DAY
The upcoming International Earth Day offers us the opportunity to kick-start our weakened resolve and commitment towards the 'Green Revolution'.
Recycling and conservation are powerful tools mankind can employ to arrest the indecent rate at which we are stripping Earth of her resources. In Singapore, some doubt what a small nation like ours can do. And even those who are willing, sometimes find things that seem to work against their 'green' endeavours.


Hougang resident Clara Heng says "There used to be special wire bins for cans, paper and plastic products in my neighbourhood. My family would religiously do our bit twice a week. Then after six months, for some reason, the bins were taken away."

Mr Tan EkLeng, a Tampines resident says "People would throw anything in the bins. It was utterly discouraging." But Mr Tan feels that with sustained public education, people will get into the swing of things.

Alicia Raj, a 22-year old private student from Bedok encountered problems with recycling. She says "How are we supposed to dispose of old newspapers when some garang-gunis don't accept them these days? They only want old televisions, radios and computers! Many people I know want to be environmentally friendly but they always hit a snag and are forced to dispose of recyclable materials improperly." Ms Raj is aware of recycling bins near the Bedok Central area but without a car, it is too inconvenient for her family members to take a feeder bus to dispose of their recyclables.

SMALL ROLE, BIG IMPACTThe combined efforts of individuals and the community can do a lot to upkeep the planet's wellbeing. Experts say all that really needs to be done is for everyone to take care of their immediate surroundings, manage their lifestyles along environmentally-friendly lines and get children actively involved.

The cumulative effect of simple tasks like cutting down electricity and water usage, consuming food in environmentally friendly packages and walking over short distances instead of driving will have a big impact on the environment.

Buy green products, especially detergents, soaps and cosmetics, and be on the look out for products that make use of recycled materials. You might also consider doing your marketing using a carrier or basket to save on the number of non-biodegradable plastic bags that you end up taking home.

At the end of the day, it's really a matter of how serious and committed we are in ensuring that our world will thrive. Temperamental as Mother Nature may be, she is the guardian to our beloved planet.

Read Users' Comments (0)

0 Response to "Mother nature's fury - are we safe from it?"