Tuesday, November 19, 2013

GeoNet 2023 Part 1: Looking back to look forward

I was recently asked to take part in a “navel gazing” exercise as a part of the eResearch2020 project and it got me thinking about both where GeoNet has come from, but more importantly, where we are going over the next decade. What will be the big changes? Where will sensor and data processing be at in another 10 years? Is the past a good predictor of the future? So first let’s look back to look forward in this first part of a short blog series.

In the beginning ….
In 1982 I was employed to investigate the possibility of collecting all New Zealand’s seismograph data centrally and electronically in Wellington. In those days all earthquake recording required those rotating drums and needles that movie sets so love. And most of the recording was done onto film which needed developing before use. I quickly established that the cost of digitally recording and transmitting all of the data to Wellington would climb into the millions of dollars (and that was 1982 dollars!). That could have been the shortest job ever – but I am still working on GeoNet more than three decades later!

Going digital ….
The solution at the time (mid-1980s) was to “go digital” and record the earthquake data on magnetic tapes that were then posted to Wellington for analysis. So I worked on methods of identifying the earthquake signals in the background noise caused by the weather, people and other animals. We could only record 25 MBytes (yes you read that right, mega-bytes not giga-bytes!) on each tape so we had to “throw away” most of the recorded ground signals. The world moved slower in the 1980s, but by around 1990 most of the 30 or so earthquake recording sites around New Zealand had been converted to digital recording.

Figure 1: The EARSS (Equipment for the Automatic Recording of Seismic Signals) digital seismograph which recorded on 25 Mbytes tape cartridges. Software running on a microprocessor automatically detected earthquake signals and recorded segments of data to the tape. 

Fast earthquake location, 1990 style ….
At that stage the tapes were posted to us once a week by the local farmers meaning it could take up to a month to get all the data required to locate an earthquake. The short cut was to ring the farmers who would read off earthquake wave arrival times from a paper printout. Using that information and data from seismographs around the Wellington region, we would be able to (if luck was on our side and the farmers were at home) provide a rough location and size for a well recorded felt earthquake in about an hour. The height of technology and science at the time!

I have just checked - the last tape from those old “tape seismographs” was received and read in mid-2005, only a little over eight years ago. By then we had made the huge change to recording ground shaking continuously at our seismograph sites and transferring the data to our data centres almost instantly for analysis. For many years following 2005 our earthquake processing, although now much faster, still required manual intervention to achieve acceptable results. All locations sent to the GeoNet website were reviewed by a seismologist before publication – a process requiring about 20 minutes.

A new beginning ….
From the beginning of GeoNet in July 2001 we progressively replaced the tape seismographs,  added other sensor technologies and increasing the number of sensor sites from around 60 in 2001 to over 600 in 2012. Then in 2012 we introduced GeoNet Rapid with automatic earthquake processing and reporting including a blow-by-blow record of the “history” of the earthquake location process published directly to the GeoNet website.

Next blog - GeoNet 2023 Part 2: The here and now