Cracking bin Laden’s computer code: unlikely

By Jennifer Seberry, Professor of Computer Security at the University of Wollongong.

It has been reported that Osama bin Laden’s hard drives have been seized, hard drives that could conceivably contain information regarding the membership, funding and future plans of al-Qaeda.Information of this type would help anti-terrorism agencies enormously.The hard drives were recovered from bin Laden’s compound in the Pakistani city of Abbottabad and are said to be encrypted with a encryption method known as AES-256.AES-256 is the current world standard for data encryption and is used by the likes of Wikileaks and the US Government to encrypt sensitive information.

How it works

To understand how encryption works, you first need to understand binary.

The smallest possible piece of digital information is known as a bit. This piece of information can have one of two states: off or on, 0 or 1.

Computer encryption works by taking data in this binary form – a stream of 0s and 1s – breaking it into blocks 256 bits long and then entering this block into a special encryption algorithm.

This algorithm is designed to cause as much confusion as possible by using a “secret key” which also comprises 256 bits of binary data.

If you know the encryption key you can “decrypt” the data and return it to its original form. For this reason, encryption keys are kept secret.

(This short animation created by Enrique Zabala from Paraguay demonstrates just how complicated the AES encryption process actually is.)

Data encryption using the AES is ubiquitous. It is used by banks, business, governments, and in computer programs such as Skype.

Where did AES come from?

In 1997, representatives of the US Department of Commerce called for cryptologists around the world to submit an encryption algorithm that would replace the previous standard: Data Encryption Standard (DES).

As director of the Centre for Computer Security Research at the University of Wollongong, I was part of a research group that submitted an entry, called LOKI, a symmetric encryption algorithm.

Our algorithm was quickly removed from contention in the global competition as other researchers found ways to get around our encryption method.

The winning algorithm – developed by two Belgian cryptologists, Joan Daemon and Vincent Rijmen, and known as Rijndael – was selected by the cryptographic world community and announced by the US Government as its Federal standard on May 26 2002.

The name Rijndael was chosen as a combination of the authors’ names and as a gentle poke at the fact few people can pronounce Flemish names without getting their tongues-tied.

The compound in Abbottabad, Pakistan, where bin Laden was killed on May 2. EPA

Getting bin Laden’s data

Because the US Government was involved in the creation of this encryption scheme, there have been rumours in recent days that they may have covertly engineered a so-called “backdoor” into AES-256, allowing top US officials to decrypt any data encrypted using this method.

I personally don’t believe this “backdoor” exists, for the following reasons:

1) The open process by which candidate algorithms were submitted and analysed by the world cryptographic community would seem to render this impossible.

2) The fact the technology has been widely accepted by many, non-American governments (and apparently bin Laden) would suggest its robustness.

3) The process used in the encryption is both “state-of-the-art” and, in computing terms, “best practice”, which would make vulnerabilities of the type allowing a “backdoor” unlikely.

Assuming bin Laden’s files are indeed encrypted using AES-256, the only way I can see to break the encryption would be to use a painstaking “brute force” technique.

This would involve trying all of the 2²⁵⁶ possible encryption keys. This works out at 1.16×10⁷⁷ different codes to try (the number one with 77 zeroes after it).

This process would require hundreds of thousands of specially-built machines, the likes of which do not currently exist. Even if they did, we would need many, many times the length of the universe’s lifespan to carry out the search.

In other words, it’s not going to happen.

Assuming bin Laden’s data is encrypted using the AES-256 method, the US will be lucky to learn anything from his hard drives about al-Qaeda’s plans.

This article was originally published at The Conversation.
Read the original article.

Occupying Wall Street and Remembering the 1960s

When I was interviewed recently about the Wall Street protests by Triple J and Brisbane’s ZZZ, I stressed their significance as symbolic politics but expressed doubts about comparisons being made with both the Arab Spring revolts and the radical movements of the 1960s. Yet since these interviews the protests have grown and spread across America in a way that does compel some serious speculation that a new movement for social change is developing. Participants and commentators from my generation (broadly speaking the baby boomers) are heartened by the number of young people involved.

These young people are witnessing a massive decline in job opportunities at the very time that many of them have increasing debt due to heightened student loans. They also face a world in which the richest 1% prosper while the middle class shrinks, working class salaries are effectively cut, the official poverty rate is now above 15% (whereas ten years ago it was at 11%) and black rates of poverty and incarceration signal an intensifying racial divide. The protestors in Wall St. want to turn that world around, want the financiers to be held accountable for the wreckage they have created, want a more equal society and one that does not squander its wealth on the military industrial complex and imperial adventures abroad. Sounds like the Sixties? At one level, yes, but at another not quite.

Was Einstein wrong? The CERN experiment that could change modern physics

Einstein’s special theory of relativity rests on two postulates: a) there is a maximum speed at which particles can travel through space and b) this maximum speed is the speed of light. The special theory of relativity becomes important when speed of particles approaches the speed of light. For lower speeds, it gives the same results as the Newtonian mechanics. The general theory of relativity was developed subsequently, to describe the gravity based on relativistic principles. These theories have been verified in a large number of experiments, setting foundations of modern physics.

However, a recent report questions the validity of one of the two postulates of the special theory of relativity.  In an experiment called OPERA, elementary particles called neutrinos were produced at CERN and directed towards detectors in an underground Gran Sasso laboratory, 730 km away inItaly.  Neutrinos are particles that do not interact with matter almost at all and they were passing almost unobstructed through the rock/soil formations on their way to the detectors.  Measuring the time it took to the neutrinos to travel the distance of 730 km, the physicists came to a surprising result: the neutrinos had to travel with the speed 0.0025 % faster than the speed of light. Careful rechecking of the experiments confirmed that the accuracy of their results is better that the obtained difference between the speed of light and the measured speed of neutrinos. While the difference of 0.0025% may be minute, this result is challenging one of the basic pillars of modern physics.  This finding is being tested by other groups. If proven correct, it will require modifying the basic theories of physics.

Wowsers are traditionally as Australian as meat pies and Holden cars, says Associate Professor Gregory Melleuish.

WHEN we survey some of the more controversial incidents of recent times, from the attempts to place restrictions on poker machine players to the suspension of live cattle exports to Indonesia, there is a connecting thread that almost everyone has missed. This is the return of the wowser.

Wowsers (We Only Want Social Evils Remedied) are traditionally as Australian as meat pies and Holden cars.

They were responsible for Australian institutions such as the six o’clock closing and the shutting of shops on Sundays.

One would have thought that they had receded into the annals of history as Australians became more liberal on these sorts of issues. Shopping is now very much a Sunday experience and Australians are used to the idea of civilised drinking.

But wowserism has never really gone away and, like any great tradition, has bided its time waiting for new opportunities. It has simply changed its spots. Once it had a strong religious colouring; now it is taking on an increasingly secular tone.

Wowsers want to improve people and make them better. To do so they have to prevent them from engaging in activities that they find immoral: be it gambling, eating meat, drinking alcohol, smoking or consuming junk food.

My father used to say that for such people if you were enjoying yourself there must be sin involved.

I have no doubt that behind the ruckus about live meat exports there is a vegetarian agenda, based on the idea that vegetarians are better people than meat eaters. If we limit gambling we can make people better. And, as we all know, it is a fact universally acknowledged that there is not a bogan out there who could not do with some improvement.

In days gone by, the ideals of wowserdom were often linked with those of eugenics. People could be improved if only their habits and lifestyle were changed; if only they lived a more rational way of life.

Eugenics has often been misunderstood. For one thing it was embraced in countries such as Australia by people who considered themselves to be progressive, who we would describe as being on the left. For another it was as much about changing the environment as it was about selective breeding. It was about making better people.

25 Years at UOW – “what a privilege”, says Prof. Gordon Wallace

Twenty five years ago I received a call in my University College Cork office from Prof. Leon Kane-Maguire, then Head of Department of Chemistry at University of Wollongong. I did not know that call was about to change the course of my professional life – allowing me to embark on an incredibly exciting research journey.

This year I celebrate 25 years “service” to the University of Wollongong. Arriving in Wollongong I found myself in a University keen to establish international research credentials and to be innovative in the approach that was used to do that. I have been privileged to be caught up in and to be allowed to contribute to that exciting venture. A start up research grant of $2,000 (AUD) was proudly negotiated by Prof. Kane-Maguire and the University hierarchy (I guess). Start up research funds at other Universities were significantly greater but I have since learnt that enthusiasm, camaraderie and the working environment (eventually) outweigh any lack of funding available.

I was fortunate that at this point in time some of the best PhD students in Australia were also attracted to this challenging dynamic and rapidly growing research environment. Together we forged viable research activities, faced with the challenge of balancing applied research (the major source of our support at that time) with our desire and need to build a strong fundamental research base. A research theme emerged that could satisfy these twin desires and was “sexy” enough to generate interest at all levels in our community – it was intelligent polymers. Polymers, for example, that could monitor and respond/shut down corrosion or that could detect biological imbalances or imperfections and correct them. The concept was indeed visionary (perhaps more so than we thought at the time) with short term outcomes possible and the longer term continually presenting us with significantly more research challenges. Twenty one years later (2011), the Intelligent Polymer Research Institute has come of age and the science is as intriguing as ever. We are excited by on-going discoveries and enthused by the outcomes we see possible by integrating multifunctional behaviour into devices at the molecular level.

Food Security a Real Issue

Professor Linda Tapsell

Recent natural disasters have led to the phrase – ‘food security’ – being used with increasing frequency. With floods devastating our banana plantations up north; drought conditions affecting  wheat crops in West Australia; and earthquakes in New Zealand and Japan, there is no doubt that food security is something to think about today.

But what exactly does food security mean? Essentially, it is about having enough food that is good for you. Yet it is more than a measure of the amount of food that is or isn’t available. Food security is also measure by the quality of nutrition and prevailing social and economic factors.

Food security is in fact a population health concept which requires constant monitoring and attention. The United Nations Food and Agriculture Organisation (FAO) refers to food security in terms of all people at all times having physical and economic access to sufficient, safe and nutritious foods. These foods must meet dietary needs and food preferences for an active and healthy life. 

On a national and global scale, food security covers food production and trade. The effects of floods, bushfires, hurricanes, earthquakes and droughts are all considered when assessing the quantity of food being produced and available.

It is also assessed on a scale of nourishment. Even when there is plenty of food, the nutritional quality of this food is an important determinant of food security. It is possible for individuals to not meet all their nutrient requirements in conditions where poor food choices are made in the midst of plenty. For example, the problem of obesity is also a problem of food security because it reflects an imbalance in meeting nutritional requirements.

From a social perspective, food is an integral part of cultural conditions.  Having access to foods that people recognise as staples and are able to prepare in safe and nutritious ways is another important dimension of food security.  This is what ‘meeting food preferences’ refers to. The provision of food must be considered in context where traditions and usual eating patterns are reflected in the nutritious foods that are provided.

Australia has a great deal of expertise in food security. In particular, it has special expertise in agriculture that can be applied to food production where there is climate variability.  Economically we have influence – Australia produces enough food for 60 million people, triple our population, and food trade is an important part of our economy.  We also have extensive expertise in how food affects health, and professions such as the Dietitians Association of Australia to support the community in making healthy food choices. We have great opportunities for combining these areas of agricultural and diet expertise to produce food that promotes health for the population and with a coordinated effort from government and institutions can contribute substantially to food security in our region.

Food security can also begin at home, for example, with the community valuing food much more. This can be done by celebrating and being creative with healthy food, choosing better food for meals and snacks, learning more about good food at school, eating just enough to maintain a healthy weight, and considering the environment in our resources management of food.

An excellent, and timely, resource that our institutions, business and the community can draw on to better understand and plan for food security is the recently released Australia and Food Security in a Changing World report, released by the Prime Ministers Science Engineering and Innovation Council (PMSEIC) expert working group through the Chief Scientist for Australia (http://www.chiefscientist.gov.au/about/publications/).

As we face a number of challenges to our food security through natural disasters, social change and economic influences, it is time to embrace a coordinated approach to ensure we have enough food that is good for all of us well into the future.

Professor Linda Tapsell is the Director of the Nutrition theme at the Illawarra Health and Medical Research Institute, a joint initiative of the Illawarra Shoalhaven Local Health Network and the University of Wollongong. She is also Director of the UOW Smart Foods Centre. She was a member of the Expert Working Group that produced the PMSEIC report.

UOW ’s Research into Schizophrenia and Better Treatments

Written by Dr Elisabeth Frank
Schizophrenia Research Institute (SRI)
School of Health Sciences, University of Wollongong

 

“Schizophrenia is a devastating brain disorder that affects up to 1 per cent of the population worldwide…” is a frequently used statistic in publications on schizophrenia research. Whereas worldwide seems far away, it is a fact for our community; over 2,000 people in Wollongong alone have schizophrenia.

Schizophrenia is a chronic psychiatric disease, which has its onset mostly in the late teens or early twenties. It significantly impairs normal brain function; the neurodevelopmental hypothesis of schizophrenia assumes that it is a consequence of disrupted brain development in early-life.

Clinically, schizophrenia is divided into positive, negative and cognitive symptoms. What this means for patients is paranoia, hallucinations, a retreat from reality; total social isolation is often the result. The emotional burden on sufferers, families and friends is considerable, and the disease is estimated to cost the Australian community $2 billion every year.

There is currently no cure for schizophrenia; and though there are antipsychotic drugs, they are insufficient. Patients are medicated at high doses over their entire lifetime and the drugs cause serious immediate and long term side effects.

For these reasons and more, research into schizophrenia and better treatments is critical.

At UOW, several centres and researchers from various scientific fields are engaged in cooperative research on schizophrenia. Many of the basic and clinical researchers are found under the roof of the Illawarra Health and Medical Research Institute (IHMRI) and are associated with the Schizophrenia Research Institute (SRI).

The Centre for Translational Neuroscience (CTN) has a special focus on schizophrenia. Under the lead of Professor Xu-Feng Huang and based at IHMRI, the majority of the 30 research fellows and research students are working to uncover the neurochemical and genetic underpinnings of schizophrenia as well as neurophysiological consequences of antipsychotic drug treatment.

Studying samples from patients in Australia and China, human post-mortem brain tissue and rodent models, we use sophisticated state-of-the-art biochemical, genetic and intracranial techniques to explore neurochemical mechanisms of the disease in vitro and in vivo.

For example, the NHMRC-funded research team of Professor Xu-Feng Huang, Dr Kelly Newell and Dr Teresa Du Bois examines the glutamatergic NMDA receptor, since it is highly relevant for adequate neurodevelopment. Our second neurodevelopmental target and studied in its interaction with the NMDA receptor is the neuronal growth factor Neuregulin-1, which was identified in human genetic population studies as a major candidate for schizophrenia risk.

In a NHMRC-funded linkage project, Dr Mei Han and Dr Francesca Fernandez are screening schizophrenia patients in Beijing for mutations in this gene in correlation with symptomatology and neurochemistry. By comparing this to a Neuregulin-1 model at UOW, my SRI-funded research team is making discoveries in the novel field of neuroimmunology, which has only recently been unravelled for its aetiological relevance for schizophrenia.

 The severe side effects of antipsychotic drugs are also being investigated at the CTN. Currently available drugs have limited efficacy and are associated with a range of side effects. The NHMRC-funded research team of Professor Xu-Feng Huang investigates antipsychotic action on neurochemistry in relation to side effects like weight gain and metabolic disorders. The NHMRC-funded research team led by Dr Chao Deng is studying the functional selectivity of antipsychotics in treating schizophrenia.  These projects are expected to lead to better treatments for schizophrenia patients with reduced side effects.

 The schizophrenia research projects underway at our centre complement and collaborate with many others at the University. Working with researchers from IHMRI, the School’s of Health Sciences, Psychology and Nursing, the Graduate School of Medicine, the Illawarra Institute for Mental Health (iiMH) and the Brain and Behaviour Research Institute (BBRI), we further our understanding of disease development and treatment through combined approaches.

 We have close collaborations with the School of Psychology, where Dr Nadja Solowij, Dr Emma Barkus and several collaborators have attracted major funding for their research on the role of cannabis in the risk for schizophrenia. In a new collaborative project, an Illawarra schizophrenia patient cohort has been established. Patients will be studied by clinical and basic researchers from several schools and centres from a psychiatric, psychological, drug-compliance, dietetic, genetic, lipidomic, neurochemical and neuroimmune perspective. This will not only be a unique project due to its inter-disciplinary approach, but has the potential to directly feedback to patients and carers in the Illawarra community. Determining factors that predict a good treatment response as well as indicators for side effects of drug treatment will allow us to improve the choice of drugs used as well as to better monitor indicators for, and therefore potentially prevent, deleterious side effects in our patients.

 Linking as well with researchers from the School of Chemistry and Intelligent Polymer Research Institute (IPRI), and having access to their highly developed tools, gives us the opportunity to explore novel ways to target discovery, drug development and drug application. This is additionally supported by our cooperations with pharmaceutical companies.

 Our investment into schizophrenia does not end at the lab bench. In addition to our scientific investigations, our researchers also engage in community awareness and education around schizophrenia. With the support of IHRMI and SRI, our researchers and students have organised and contributed to a Schizophrenia Awareness Event and Mental Health Expo; and the Illawarra Mental Health Round Table which brings together major stakeholders of schizophrenia research and care in the Illawarra.

Schizophrenia is a devastating disease, but many researchers at UOW are working actively together to improve prevention, diagnosis and treatment of schizophrenia, and finally help patients and carers lead a better life. 

More information:
www.uow.edu.au/health/healthsciences/ctn/
http://ihmri.uow.edu.au/nmh/schizophrenia/index.html
www.schizophreniaresearch.org.au

Do Social Media Influence Our Travel Decisions?

Associate Professor Ulrike Gretzel

From the success of social networking sites to the explosion in user-generated content, we have seen a dramatic shift in how consumers interact with the internet and with each other. Social media have transformed the way people communicate, search for information, make decisions, socialise, learn, and share experiences.  This also applies to consumer behaviour in travel and tourism. 

Growing numbers of travellers search and consume travel information created by other travellers for their travel planning and then share their experiences when they return from their trips. Given the experiential nature of tourism, the information created by other travellers is even more important and influential in the search and decision-making process than when considering other types of purchases. 

Over the past four years we have conducted a series of studies involving travellers with Internet access from around the world. We consistently find high levels of social media use for travel planning. 

Online travel reviews, such as the hotel reviews posted on TripAdvisor, are particularly popular sources of information and those who use them indicate that these traveller opinions greatly influence their accommodation choices. Activity choices and restaurant decisions are also increasingly affected by the opinions of review writers while decisions on where to travel are typically made before reviews are consulted. 

Other social media types such videos and podcasts are generally less influential, although gender and age differences come into play when looking at the influence of specific social media categories. 

Do travellers blindly trust the opinions of strangers?
Our research indicates that trust levels are very high and that a considerable number of people even prefer the opinions of unknown others over opinions of friends and relatives. However, many consumers are also aware of marketers posting reviews or paying professional review writers. They have therefore developed rather sophisticated strategies for evaluating whether they should take a posting into account or not. 

In general, if comments are too negative or too positive, travellers become suspicious. They are looking for balance and details and take subtle cues such as spelling and tone of writing into account. Experimental studies we conducted have also shown that individuals are pretty good at detecting false reviews, and this ability increases with the length of the review.

So like in the offline world, liars will only be able to influence travellers if they are brief. We also find personality differences, with individuals who exhibit neurotic tendencies being less trusting of social media and thus less influenced by them.

Do tourism marketers have to worry?
Our studies find that a majority of travellers think that social media contents are more up-to-date, more fun to read, more interesting, more relevant, more comprehensive, more specific and more helpful in making decisions than information provided by tourism marketers. However, that does not mean that marketers do no longer provide an important function. The travellers we surveyed actually trust social media content more if it is provided on official destination marketing websites.

This is a counter-intuitive finding but makes sense if you consider that destination marketers probably subject social media contents to a basic editorial process, or would at least comment on a posting if it provided false information.

In general, our research shows that tourism marketers can no longer ignore social media and have to carefully think about how to take advantage of social media marketing in order to exercise influence on travellers.

Social media are here to stay but their specific forms will evolve. Twitter and location-based social media applications like Foursquare and Gowalla are still in their infancy and Facebook continuously adds functions and changes its policies. It is important to monitor their impact on travel planning and behaviours at destinations, so that those who try to encourage and/or manage tourism to particular places can adjust their strategies.

Written by Associate Professor Ulrike Gretzel
The Institute for Innovation in Business and Social Research (IIBSoR)
Faculty of Commerce

A geological excursion to the Shakey Isles and an account of the Christchurch Earthquake

Rock fall following the Christchurch 6.3 earthquake. Source http://blogs.agu.org/landslideblog/2011/02/23/on-the-causes-of-the-high-levels-of-loss-in-the-christchurch-earthquake/

Posted 28 February 2011

Last week 11 students and staff from the School of Earth & Environmnetal Sciences (SEES) returned from a geological fieldtrip to the South Island of New Zealand to investigate active tectonic processes including the fault rupture from the magnitude 7.0 earthquake in Christchurch last September. Little did we know that a second large earthquake (magnitude 6.3) would devastate much of Christchurch only 5 days after our return highlighting the unpredictability associated with seismic hazards. 

The fieldtrip was organised by two SEES PhD students, Steph Kermode and Nathan Jankowski, who head up the student social group – GROUNDSWELL and was supported by SEES staff Brian Jones and Solomon Buckman. The students included a mix of postgraduates and undergraduates from all levels. The purpose of the trip was to observe active tectonic and glacial processes that have sculpted the landscape in New Zealand that are not readily observable in the relatively stable Australian continent. The long-term aim is to run this fieldtrip each year as an intensive field-based summer subject in which students can get first hand experience of active geological processes including volcanoes, geothermal power stations, glaciers and faults associated with active mountain building.   

The landscapes and mountains of New Zealand are incredibly young with most of the relief having formed in only the last 5 million years. This is in stark contrast to the Australian continent that has not experienced any major mountain building activity for the past 200 million years and subsequently been eroded down to a vast, flat continent. Despite the contrast, Australia and New Zealand share a common geological origin as they were joined together 85 million years ago as a part of the supercontinent Gondwana. Between 85-45 million years ago New Zealand rifted away from Australia creating the Tasman Sea that now seperates the two continents. New Zealand is situated directly on the boundary between the Australian and Pacific plates making it a particularly active in terms of volcanic and seismic activity. In the North Island the Pacific Plate is moving to the east and subducting (sinking) beneath the North Island resulting in the development of an active volcanic arc and a deep sea trench to the east which extends all the way to Tonga. To the south subduction has flipped with the Australian Plate subducting beneath the South Island to form the Macquarie Ridge and Southern Alps. In between the North and South Islands is an intense zone of faulting where the New Zealand continent is being wrenched apart by the Alpine Fault. This is a major transform (strike-slip) plate boundary and has been active for the past 25 million years. The Alpine Fault consists of many subsiduary fault splays along its length. The big surprise with the Christchurch earthquakes has been the fact that Christchurch has not experienced large or regular earthquakes in historic times and that the fault line has not been identified  due to it being buried by thick sequences of river sediment that has been eroded off the Southern Alps. Christchurch is also quite a distance from the Alpine Fault which may have built a collectively false sense of security. New Zealand is referred to as the Shakey Isles for good reason. It sits on the Pacific Rim of fire and is subject to regular, intense seismic activity as the tectonic plates jostle and collide with each other.

It was clearly evident when we visited Christchurch that it was still rebuilding from the September 3, 2010 magnitude 7.0 earthquake that struck 45 km west of the city in the rural outskirts of Roleston. It is important to realize that the Richter scale used to measure the magnitude of earthquakes is a base-ten logarithmic scale so an earthquake measuring 5.0 has a shaking amplitude ten times that of an earthquake of magnitude 4.0. However, the total energy released is 33.3 times the amount for a difference of 1. Put simply a difference of 2 on the Richter scale results in about 1000 times the amount of total energy released. Most movement on faults is accommodated by large earthquakes. Unfortunately earthquakes remain difficult to predict in the short time-scales useful to people due to the numerous variables – build up of stress, time since last rupture, water saturation of the fault plane and most importantly the fact that earthquakes generally occur 10’s to 100’s km below the surface where we cannot make direct observations of the physical conditions. Geologists rely solely on geophysical and seismic data to interpret conditions and structures deep in the lithosphere.

We visited the fault rupture and although the roads had been repaired the 4 m offset of roads, fences, hedges and canals was clear to see as well as numerous cracks and compressional mounds along the fault trace. It was also evident that many of the locals weren’t happy with the attention they were getting from passers by like us who wanted to stop and view the fault. There was a real sense amongst Cantebrians that they were lucky to get away without any loss of life after the first earthquake. Unfortunately that was not the case with the recent earthquake in which the death toll has just passed 100 and there are still over 200 people missing.

The epicenter of the February 21, 2011 magnitude 6.3 earthquake was only 5 km from the centre of Christchurch with the epicenter centred on Lettelton.  Because of proximity to the epicenter and the shallow depth (5 km) of the hypocentre, ground shaking in Christchurch was much more severe for this latest earthquake than for the larger magnitude 7 event in September. Ground accelerations were unusually high for this event, probably due to the shallow depth of the earthquake hypocenter and the thick unconsolidated substrate of wet mud and sand that much of Christchurch is built on. Compared to solid rock, sands and muds have the effect of slowing and amplifying seismic waves as they travel through the earth resulting in greater shaking. Wet sediments are also prone to liquefaction when shaken which means they suddenly change from behaving as a solid during normal conditions to a liquid during an earthquake. During an earthquake liquid sand or mud can spew out of cracks in the ground and flow down roads and collect in depressions and drainage networks. Heavy buildings and structures will tend to sink and become unstable during liquefaction if they do not have adequately engineered foundations. Typically ground shaking is in the order of 25%g  for a magnitude 6.3 earthquake but the Christchurch earthquake produced shaking of up to 188%g. To put this in perspective, any shaking above 100%g is enough to overcome the acceleration of gravity and start throwing objects up in the air! Although New Zealand has a very strong and strictly enforced earthquake building code, this level of shaking resulted in severe and widespread damage. The Modified Mercalli Intensity scale (I-XII) is used to measure damage based on observations and interviews. Levels of IX to X were recorded around the epicenter which means intense to violent damage of well-built stuctures and damage or destruction of some well built wooden structures. Most houses are built of wood in New Zealand because it is much more flexible and resistant to earthquakes than brittle brick structures. Unfortunately, aftershocks can occur for many months after an event creating dangerous conditions in already weakened structures. The other aspect is that where stress is released by an earthquake it can result in increased stress along other faults segments resulting in an “unzipping” effect as stress in the crust is redistributed and comes to a new equilibrium. This appears to be the case with this second magnitude 6.3 earthquake following the magnitude 7.0 earthquake last year some 45 km further west.

Part of my research involves investigating evidence of ancient earthquakes (Paleoseismology) in areas of Australia that are prone to seismic activity and I have a PhD student – Chulantha Jayawardena, investigating active faults in the Adelaide region. Although Australia is relatively stable compared to New Zealand it is still affected by earthquakes as evident by the magnitude 5.6 Newcastle earthquake in 1989 and the magnitude 5.4 Adelaide earthquake in 1954. Earthquakes in Australia are referred to as intraplate earthquakes as they do not occur on plate boundaries and are much less understood and certainly less predictable in terms of their distribution. The danger with these intraplate earthquakes is that they may have long recurrence intervals of 100’s or 1000’s of years before the crustal stresses build up enough to rupture and generate an earthquake and they can strike areas that are underprepared for such events. We are investigating active faults along the margins of the Mount Lofty and Flinders ranges in South Australia by way of trenching, mapping and using ground penetrating radar to identify previous ruptures. Some of these faults have rupture lengths and offsets of single events that suggest magnitudes in the order of 5-7 on the richter scale. Part of our research involves dating these paleoseismic events by sampling the sediments that have accumulated adjacent to the fault rupture using luminescence dating techniques (OSL) to further constrain the timing of past earthquakes. Identifying hidden fault lines and constraining the timing of past seismic events is of fundamental importance in understanding how mountains such as the Flinders Ranges form in intraplate settings and of course it has important practical implications in terms of planning and implementing appropriate building codes in earthquake prone regions of Australia.

Earthquakes are a global hazard that knows no political boundaries. Earthquake response and rescue efforts are often globally assisted and require the expertise of many disciplines including engineers, geologists, planners, medics, police and emergency response personnel. Earthquake mitigation is an ongoing process from the initial identification of faults and historic seismic activity, through to developing appropriate building codes, to the rescue efforts when these hazards strike through to planning for the next event. The tectonic processes so evident in New Zealand provide an important modern-day analogue in terms of understanding how older continents like Australia have been shaped and formed in the past.

For further information please contact Dr. Solomon Buckman solomon@uow.edu.au in the School  of Earth & Environmental Sciences

The Queensland floods, climate change or poor planning?

Professor Gerald Nanson

A number of media commentators and numerous letters to the editors in major newspapers have suggested that the recent floods in Queensland are some sort of bellwether of global warming and Australia’s hazardous climatic future in a warming world. There is no doubt the globe has been warming over the past century or so, and it seems very likely that this is a function, at least in part, of our introduction of excessive Greenhouse gases to the atmosphere. But Australian weather is far too variable today, and indeed has been so for thousands of years, to enable any confident predictions to be made about the changing magnitude and frequency of extreme events. The last major flood on the Brisbane River was in 1974 which coincided in many places with the most extreme flood events continent-wide since European arrival. So while we have just two such truly ‘catastrophic’ flood events in our recorded history, it is very difficult to say anything scientifically sound about their changing magnitude and the likely frequency of their occurrence. Scientists sometimes use smaller events analysed statistically to predict the likely size and frequency of extreme events, but Australian climate is well known to move in cycles, several decades in length, which commonly result in clusters of decades producing very different conditions to those before and after. Indeed, our natural climate is something of a rollercoaster ride. When ‘old timers’ timers say that a particular flood is the largest they have ever seen in their area, it isn’t necessarily because climate is changing, it’s mostly because even ‘old timers’ don’t live for hundreds of years. Global movement of the ‘climate goalposts’ can be used as an excuse for poor urban regional planning. There is abundant evidence of extreme flood risk in many areas of Australia, including in Brisbane, and much of this evidence was collected before global warming was an additional significant variable to consider. The human cost of flooding in Australia is mostly the product of poor planning, not climate change.

Professor Gerald Nanson is from the UOW School of Earth and Environmental Sciences

 Read another short essay from Gerald :
“The floods of Queensland have raised important issues relating to how well Australia collects data that is vital for the accurate analysis of potential hazards, and how adequately our country understands and therefore is prepared to deal with our extreme environmental hazards.”  More at: http://media.uow.edu.au/news/UOW094233.html