Vibration data is being collected by an array of sensors (nicknamed “shakes”) in Evanston campus research buildings.
Data guides:
Each shake produces more than one data stream. Data recorded and streamed from channels starting with “EH” represent variations in ground velocity and data recorded and streamed from channels starting with “EN” represent variations in ground acceleration. Channels ending in “Z” represent vertical motion, channels ending in “N” represent motion in south to north direction, and channels ending in “E” represent motion in west to east direction. Data recorded and streamed from channels named “HDF” represent variations in atmospheric pressure. The shakes are particularly sensitive to variations that occur with frequencies larger than 0.7 Hz and smaller than 50 Hz.
Sound waves represent variations in atmospheric pressure as well, and occur in the audible spectrum with frequencies largely above 50 Hz. Therefore, we call our lower frequency sound signals, recorded by the HDF channels, “infrasound”. Infrasound is measured in units of Pa (Pascal). Ground motion is measured in m (meter), or m/s (meters per second), or m/s2.
These analyses and documents were authored by Suzan van der Lee, Ann Thomas, Lucas Schirbel, Yoweri Nseko, and Albert Kabanda of NU’s Weinberg College of Arts and Sciences’ department of Earth, Environmental, and Planetary Sciences.
The shakes locations are as follows: