Friday, August 26, 2011
Out in the field - Canterbury : Day 2
Another beautiful day, our first two stops were temporary sites, where we changed over the batteries and retrieved the data cards.
Both sites are on farm land and we are always grateful to the owners for allowing us access to their property, and to leave our instruments there for months at a time.some farmers are fantastic and even give us a hand, the pics right and below show the fantastic views from one such farm, where the kind owner helped us get our heavy batteries up and down the hill on his quad-bike.
We then went out searching for ideal test sites for permanent seismic stations. After the scientists have located ideal areas on maps, we then have to go out to the areas to see exactly how 'ideal' they are! As we need to find areas with low noise (cars, wind etc.) good base rock and relatively easy access for the techs to build them. Once we find suitable areas we then have to track down the landowners and ask for their permission. Luckily this was relatively easy today and they were fantastic, and happy for us to 'play' on their land.
Step 1 - Dig a hole for the vault
Step 2 - Concrete a paving slab to the rock below "to essentially bond the sensor to the rock" to make sure you are recording the actual earths movement, as opposed to the movement of the loose earth around it.
Step 3 - Put the seismometer into the 'vault' - it has to be perfectly level and point north to allow us to derive direction to the seismic waves/earth movement. A lid is then placed on top and the earth filled back into the hole.
Step 4 - Connect the seismometer to the Taurus (data logger) and battery (power), and package up all nicely into a tarp to protect from the weather.