NZ3D Blog #3: Seismometers come in all shapes and sizes

Seismometers come in many shapes and sizes. In this project we’re using three types; Guralp 6TDs, GFZ cubes and GeoSpace GSXs. And as the NZ3D team have all had to learn, each is installed differently. The 6TD is our all-singing, all-dancing, self-charging, 3-component broadband quake-measurer. Like a superhero, but one that requires some serious manual labour and technical know-how to put in action…

The 6TD is put to bed in a 60cm deep hole pointing North and precisely levelled using a spirit level. Through a myriad of cables, it is hooked up to a car battery, which is recharged from a solar panel. The GPS records its location and a fence is built around the site to protect it from curious livestock and locals. With soft ground, no technical hiccups and team of keen beans, this takes about two hours (not including the off-roading and site scouting I described last time)!
​
The cubes, by comparison, are a walk in the park. Literally! They may not be broadband superheroes but we can strap them to our backs and stroll up valleys and across ridges to sites which would be hopeless had we been lugging the amount of gear required for the 6TDs. Plus, all they need is a 10cm hole, a couple of batteries, pop a box over the top and hey presto!