If all is well, you received a TC1 seismometer, a computer with everything installed, and a flat-packed protective case.
Unpack the computer and TC1. Plug the power, the usb keyboard/mouse and ethernet cable into the computer.
Connect the TC1 to the computer with the USB cable in the USB port marked “TC1.”
Hook the magnets to the slinky attached to the inside of the top cap of the TC1.
Lower the magnets into the tube so that the bottom magnet is inside the copper damping ring and the top magnet is inside the coil.
Level the magnets with the three knobs on the legs. The goal is to make sure the magnets do not touch the rings.
Also, make sure the top of the magnets are flush with the top of the copper ring and coil, respectively. Small adjustments to the vertical position of the magnets can be made with the knob on the top lid.
Now turn on the computer. All the necessary software to display your seismic data will turn on automatically. The most recent versions of the station software include a standard slide-show that explains the TC1, has acknowledgements, a map of NZ latest earthquakes (data courtesy of geonet), and the seismic data from your station.
You can turn the slide show on and off in the bottom
control panel. Just go the bottom of the screen with your mouse, and the button will appear.
Maybe most importantly, you need a Station Manager. A teacher would be the most logical choice, but it could be a parent. The station manager does not need to be a seismologist, but someone who can field basic questions from students, solve small problems with the station, and relay bigger ones to us for troubleshooting.
To give you an idea on how your class project may go, you can watch this video.
Head of Science at Rangi Ruru Girl’s School, Keith Machin, wrote a wonderful article about Rangi’s first experiences in the Ru network of TC1 seismometers. In the article, Keith also proposed 10 lessons for teaching the topic of earthquakes.
In the Science Centre of the City Campus of the University of Auckland we record seismic waves with the TC1 seismometer. Routinely, our station AUCK records seismic waves from earthquakes in New Zealand and beyond. On January 20th, 2014, an earthquake occurred on the South side of the North Island, 15 km east of Ekatahuna. Here is a map of the epicentre, our station location, and the great-circle path between them.
On the left you can see 10 minutes of recordings, starting at the origin time of this earthquake. The green marker annotated with a Pn is the predicted arrival of the first wave traveling 4 degrees from the epicentre, 15 km east of Eketahuna, to Auckland. This prediction is based on a spherically symmetric model of the Earth, by Brian Kennett, and certainly seems to mark the start of minutes of vibrations in Auckland from this earthquake. In fact, if you look carefully you see that the wiggles after 10 minutes are still larger than before the first wave from this earthquake arrived. Larger earthquakes can make the Earth “ring” for many hours.
In the image on the right, we zoomed in on the first-arriving wave, almost exactly one minute after the earthquake originated. Now, you can see that the prediction is actually a few seconds before the arrival. This means the lithosphere under the North Island of New Zealand is a bit slower (~3% on this path) than the average on Earth. In general, a hotter lithosphere is slower than a cold one. This makes seismic waves traversing old, cold, continents relatively fast, and those sampling younger lithosphere like ours in New Zealand, relatively slow.
In general, it is these small travel time differences that provide images of the (deep) earth through a process called seismic tomography.
Given the usual limitations of our (vertical) sensor when it comes to S-wave recordings, this is indicative of a very deep earthquake. The USGS estimates that this earthquake happened at a depth of 460 km. Now, under most places on Earth the rocks at those depths are too ductile to support the brittle breaking necessary for an earthquake, but in this case, the earthquake happened in — or on the boundary of — the brittle Pacific Plate subducted under the Australian Plate. Note that the epicentre of this event is about 500 km from the surface expression of the boundary between these plates. From the depth of the event and the offset to the plate boundary at the surface, we can estimate the angle of subduction may be around 45 degrees.
The P- and S-wave markers are based on the average wave speed in the earth. In this case, they are a bit earlier than expected, because the subsurface between earthquake and the AUCK recording station is slower than average. As discussed previously, this is indicative of a young, warmer (and thus slower) lithosphere.
Furthermore, such deep earthquakes cause relatively little surface wave energy. The signal after the S-waves is likely a guided wave in the Pacific plate called a “leaky mode.” If you want to learn more about leaky modes in the Kermadecs, you should read this paper.
On a mac, there is this clever tool to turn off (parts of) applications that the computer thinks you are not using. This tool is called ‘app nap’.
For jamaseis, this has to be turned off. The following video shows how:
(Note: The initial part of the video shows how you can access the relevant settings by right clicking. You may need to hold down the control key on the keyboard while clicking to get to the contextual menus).