Vol. 3 No. 2 (2024)

Cover caption: Kane Springs Tower, a 36-m-high Wingate sandstone tower in southeastern Utah and the subject of more than two years continuous seismic monitoring by a team from the University of Utah. Typically getting to the top of tall towers requires technical climbing, but this site is uniquely accessible being separated from the adjoining cliff by about a meter-wide gap, crossing which provides access to the mostly level working area on top. Nevertheless, getting to the top of the cliff was a difficult hike with no trail up the steep boulder-strewn slope, one that the research team often found many various words to describe, and some field assistants swore they would never do again. The rock tower vibrates at a clearly resolved fundamental resonance mode (around 1 Hz) whose frequency drifts over the year and on the daily scale. Interestingly, while the few other similar datasets reported show that frequencies vary directly with temperature sometimes with or without a phase lag, data from Kane Springs Tower shows that frequency changes actually precede seasonal temperature changes. This curious observation led the research team to discover that the annual pattern of insolation is actually controlling annual frequency drifts, and that aspects of daily drifts are similarly controlled by insolation patterns. Credit: Jeff Moore