What is the difference between the RSD3 and RSD4? I don’t live in a seismically active area but I still want to buy the best raspberry shake I can alongside my Shake&Boom, I was orginnaly going to go with the RSD4 but then I saw the RSD3 is more expensive, why is this? Does it mean it’s better, what is the main difference between the sensors?
RSD3: All axes Earth Motion Sensors (Vertical and lateral geophones)
RSD4: All axes Earth Motion Sensor (Geophone + MEMs accelerometer)
The RS4D has 3 orthogonal accelerometers for detecting strong motion in 3 dimensions and a vertical geophone for detecting weak motion in the vertical plane only. This would be ideal if you live in an earthquake prone area near a major fault, but for a lot of Aussies the accelerometers won’t pick up much - the signal just aren’t strong enough by the time they get here. Have a look at the data from 4D’s installed in Australia and you won’t see much at all on the accelerometer channels.
The RS3D has 3 orthogonal geophones to measure motion in the 3 dimensions. Geophones are better for weak signals than an accelerometer, so near a major fault / strong earthquake they would be over whelmed and clip so data would be lost, but for weak earthquake motion like we have in Australia they’re ideal.
M6.3 in Auckland Islands is a decent quake not far away but doesn’t register on an accelerometer in Tassie.
sheeny has already explained very well the differences between the two Shake models. Our RS4D is thought to be used in active earthquake areas (like California, New Zealand, Haiti, and more) where the geophones (suited for weak motion) of the RS3D could saturate during strong motion events.
If you don’t live in such areas, I recommend the RS3D to complement the RSBOOM you already have. You will be able to study earthquake waves in a three-dimensional environment (instead of the single vertical one), even from distant events. For example, with my RS3D, I can pick M6 and above from the other side of the world (~15-17000 km away) together with M2-3 local events.
I also have paired it with an RSBOOM, and this combo definitely provides an efficient solution to monitor both atmospheric events (such as strong cyclones and storms) together with near and far earthquakes.
If you require any other information, I remain available.