Considering that I was the originator of the term in the early 80s, and then first used it in print in the first Transactions, I'd like to chime in. I was describing that moment in the progression of activity that leads to an eruption when experienced onlookers suddenly go bonkers. Oh - you mean what are F&M doing to warrant the irrational displays of exuberance? It depends. When High and Gold (sometimes H alone) go from lusty splashing to steady jetting. Or when Upper Mortar begins a sustained eruption. When an experienced gazer says "it's approaching lock," it means "I'm about to act very stupidly out here." Paul Strasser _____ From: geysers-bounces at lists.wallawalla.edu [mailto:geysers-bounces at lists.wallawalla.edu] On Behalf Of Bob Mabery Sent: Thursday, August 18, 2011 2:38 PM To: geysers at lists.wallawalla.edu Subject: [Geysers] F&M - What's a "Lock"? I read with interest the detailed descriptions of the varied cycles of Fan and Mortar. Is there someplace that I can read a definition of the elements of the cycle, perhaps with photos? For example what is a "lock?" BobInGA W4YBB "Your Buddy Bob" -------------- next part -------------- An HTML attachment was scrubbed... URL: </geyser-list/attachments/20110819/de11d800/attachment-0001.html>