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January/February 2016: A Royal Rose Cushion

Craft article and original tapestry pattern for Creative with Workbox Magazine. Issue 153.

December 2015: Shoot for the Moon

November 2015: I've been busy making a new website and updating the news for the Independent Research Association of New Zealand. Check it out at

See IRANZ's latest enewsletter: Connections. With a round up of research news from New Zealand's independent science sector

November 2015: Cancer sniffing bears

October 2015: Heisenberg's Uncertainty Principle in practice

September 2015: Unpacking the Universe

August 2015: Pasta annihilation

Something a bit different. Yes, I know it's antipasto, but that doesn't work for a particle physics joke, does it?

Queen Elizabeth rose tapestry. Credit: Louise Thomas

August 2015: A right royal tapestry

The Queen Elizabeth rose is my favourite. Blousy big pink blooms present themselves mostly in long-stemmed clusters – like chummy little ballerinas, who had dressed themselves with varying success and then can’t go anywhere without their mates. This new pattern is available as a nine-page PDF for NZ$6.90.

July 2015: League of Lock Pickers
It's one of the more unusual commissions I've taken over the years; the June/July 2015 issue of The Shed magazine is featuring a group of Wellingtonians who like to get together to pick locks for fun. They are mainly IT security specialists who have developed an interest in physical security (and finding the flaws in it) as an intellectual pastime. As one of them puts it, "You are solving a puzzle where you can’t see all the pieces".

Allan Wilson Centre
2014 Annual Report

I was pleased to help the Allan Wilson Centre with their annual research report at the end of 2014. I'm very disappointed the Government has not renewed their funding this year and they will close at the end of 2015.

Imaging evolution: Mathematics of life

Marsden Fund winners review:

When genomes collide
The adaptive potential of small populations
Use it or loss it: flight-loss in insects
Evolution of cancer

Biotech Learning Hub Science News

December 2014: Mutating genes to detect cancer
Medical researchers from the UK, the US and Canada have developed a new tool that identifies mutating genes to detect the early stages of oesophageal cancer.

Science Learning Hub
science news
Science news for ages 12 to 16 years

GPS Satellite. Credit: NASA

December 2014: Quantum Clocks
Having the right time is unbelievably important for technologies that involve positioning and navigation such as global positioning systems and space navigation or for synchronisation in the world of high-frequency frenzied financial trading. To get it all exactly right, an international team of physicists is proposing a network of atomic clocks linked at the quantum level, which they say would be more accurate and stable than any individual atomic clock on Earth.

Tomorrow’s earthquake forecast is. . . .

First published by Position Magazine (Australia) October/November 2007

By Louise Thomas

While it is not yet possible to accurately predict earthquakes, it is possible to estimate their likelihood or probability based on known seismic behaviours. Collaborative work by New Zealand ’s GNS Science scientist Matt Gerstenberger, ETH-Zurich in Switzerland , the US Geological Survey (USGS), and the Southern California Earthquake Center is revolutionising the accuracy of this type of earthquake forecasting. The recently developed STEP model is being used to create a time-dependent map giving the probability of strong shaking at any location in quake-prone California within the next 24-hours.

Imagine being able to check the likelihood of a damage causing quake in your neighbourhood on any given day. The residents of California can do just that by visiting to see a map showing the probability of a damage causing quake in any given area of the state. The STEP (Short-Term Earthquake Probability) model, by Dr Matt Gerstenberger of New Zealand’s GNS Science and his colleagues in the United States and Switzerland, offers real-time forecasts of aftershocks over 24 hour periods following a major earthquake.

“Much of the software we are using is homemade with the calculations being done with code written in MATLAB, but we are currently finishing porting the code to Java so that it can become part of the Open SHA (Seismic Hazard Analyses) project. We get the real-time earthquake data and maintain our earthquake database using QDDS (Quake Data Distribution System), a USGS tool. The final map images are created and maintained with a variety of scripts and includes the use of GMT (Generic Mapping Tools).The online map is refreshed every 30 minutes as new data feeds in,” says Dr Gerstenberger.

The resulting map shows the probability of experiencing Modified Mercalli Intensity (MMI) VI shaking, (the level of shaking from an earthquake that would throw objects off shelves and cause minor damage). The MMI does not measure the magnitude of the earthquake itself, (magnitude describes how much energy was released in the quake), but rather the intensity of the damage done to humans, buildings and infrastructure.

“In general, we are looking at really low probabilities. It is not up to the same standard as a weather forecast, where there might be a fifty percent chance of rain. We’re at the level where a one in a thousand chance is a really high probability. The chances of you being involved in a major earthquake tomorrow might be one in a million and certain events might increase that by an order of one-hundred or more,” says Dr Gerstenberger.

Despite the usually low risk, the information is potentially useful to emergency planners and city managers who can make immediate decisions about whether to shut down certain services or even whether to enter damaged buildings if a main event earthquake does strike. This service is possible because of a seismic phenomenon known as earthquake clustering which Dr Gerstenberger and others have developed into a computer model to copy what happens in nature.

“After any event there are some well understood laws that can describe the total number of aftershocks that you can expect to have. It is one of the more understood things in seismology. So you can know the rate at which earthquakes in an aftershock sequence can occur and the overall number, following what’s known as the ‘modified Omori law’ for the temporal decay of aftershock rates. Then to get the size distribution, that’s how many large events and small events we can expect, we use the Guttenberg-Richter law which describes the frequency-magnitude distribution of earthquakes.

“Aftershocks are usually smaller than the main event, but there are some variations on the number of aftershocks for reasons not fully understood. There are theories to do with the state of stress in the crust. Earthquake clustering or aftershock sequences are a bit like radioactive decay on a Geiger counter, aftershocks occur at a defined rate but the time of any one is random, although we can determine the probability of an event occurring within a particular time frame. For a large mainshock the aftershock sequence can go on for a number of years after the mainshock has occurred, but the rate of occurrence slows down.”

Models such as STEP have a number of different data sets which feed into them to create the probability scenarios. These include geological information about positions of hundreds of faults, geophysical information about how these faults behave (such as length, shear plane, expected magnitude and reoccurrence interval), statistical information about how these faults behave over time, historic earthquake data, and modelling of how seismic activity such as precursory earthquakes and main shock events can affect subsequent aftershocks. In the case of the Californian earthquake forecast map, earthquakes, large and small, that are recorded by the California Integrated Seismic Network (CISN) feed into the model.

“There is two different parts to the map, there is the time dependent part which is always changing and that’s just purely on recent seismicity, and earthquakes in general that have happened in the last 10 to 15 years. Then there is the static, or time-independent, part. In that is fault information, and historic earthquake information which comes directly from the California portion of the USGS’s National Hazard Seismic Map.”

Dr Gerstenberger says that public access to the map is useful as it reminds people of the dangers they live with when they live on tectonic plate boundaries.

“Anything that prompts people to do the normal safety things like knowing how to turn off the gas and water, and store water is useful. In addition, although most people know that aftershocks usually follow a major earthquake, the map will tell them where these aftershocks are likely to occur and how the risk changes over time following the main shock.”

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Site last updated: 1 February, 2016.
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