On the day of the 1989 earthquake, I was at work in an L-shaped building in ANZAC Park, Canberra. I was talking with the director when we heard the two halves of the building grinding together.

You could feel swaying. So Iheaded down to the basement of the seismic section to check the drums that recorded earth movements.

We didn’t really know where the quake was located for the first two hours and it took us a day to work out the depth of 15 kms.

The 1989 earthquake was felt widely across NSW.

We knew about 19th century earthquakes from newspaper reports. There was a cluster of earthquakes in Newcastle between 1837 and 1841, when there was an earthquake at least once a year every year, in a similar location to the1989 earthquake.

1989 was the strongest since European settlement but the other earthquakes were all around 5 on the Richter scale.

The 1925 earthquake, which damaged Christchurch Cathedral, was almost as strong as 1989.

Now seismological information from Australia and Antarctica, indeed the world, is automatically sent to Canberra so we can work out location and magnitude within the hour.

It is now completely digital in comparison to the slow 1989 analogue system.

Dr David Denham

Then 52 year old Chief of Geophysics Division, Bureau of Mineral Resources, Canberra