The August heat in Texas is unbearable – today’s forecasted high temperature is 99 degF and a heat index exceeding 110 degF! TXESP’s EQ-1 vertical, educational seismograph is located in a covered garage….what effect does this extreme yield? Take a look at the images below – between 14:00 and 18:00 hrs UTC (09:00 am to 1:00 pm CST)….notice how the seismogram record (the horizontal lines) appear to be getting closer to each other? Now look at outside air temperature profile during this time period…. the outside air temperature increased from 85 degF up to 91 degF !
The dampening mechanism on the EQ-1 seismograph is motor oil. As the temperature of the oil increases, the oil expands and its volume increases. The increased volume of oil pushes the seismograph’s balancing beam upward – this upward motion creates a misleading image (shown below)…the horizontal lines appear to be coming closer together over the last 4 hours —>>> this is a direct result of the rapidly increasing air temperature! Intriguing, isn’t it.
Now, we can ask ourselves a better question – does the air temperature inside the garage increase at the same rate as the outside air temperature? What would you expect to see on the seismogram?