Updated
What a volume spike is
A volume spike compares recent trading with that coin's own recent average, inside a window you chose. The average is not one number for every coin. The same multiple on a busy coin and on a quiet coin describes different amounts of trading.
This page says what the multiple, the window, and the average mean. It does not say the spike will continue, and it does not tell you to buy, sell, or hold.
The multiple and the window
The screen calls the amount "Times the 20-day average." The default is 3×. The choices shown are 2×, 3×, 5×, and 10×. The alert also accepts 1.5× to 20×, in steps of one decimal. The name shows one decimal, so the default reads 3.0×.
The window is 15 minutes, 1 hour, 4 hours, or 24 hours. The default is 1 hour. It is the complete minutes before the current minute. The minute still in progress is left out. The check needs at least 90% of those minutes. Missing minutes are unknown. They are not filled with zero, and they are left out of both sides, so the window is compared with the average only for the minutes present.
You can set it on one coin or on your watchlist. The usual wait after a fire is 1 hour. The wait choices run from 15 minutes through 7 days.
The 20-day average
The baseline is average volume per minute over the 20 days before the window, from finished candles. It is fixed for the UTC hour. The slice starts 20 days plus the window before that hour and ends where the window begins. The window is not part of the average it is measured against.
The check needs at least 10 days of those minutes, counted as 14,400, and an average above zero. Until then it does not fire, and it does not invent an average.
The ratio is window volume divided by the average per minute times the minutes present. The alert fires when that ratio is at least your multiple, and the dollar floor below is met. Landing exactly on the multiple counts. A spike already inside those 20 days raises the average the next hour uses. The bar moves because the history moved.
A dollar floor, and the wait after a fire
The window's volume, times the price, has to be at least $10,000. A thin stretch can be many times a small average and still miss that floor. The floor is dollars at the check's price. It is not a percent.
After a fire the alert is no longer armed. It can arm again when a whole window has passed, or when the ratio falls under half the multiple you set. Half of the default 3× is 1.5×. The same halving applies to any multiple you chose. Exactly half does not arm it. It has to be under half.
Arming again is not firing again. The wait has to be over too, and the alert does not re-arm and fire in the same check. A window shorter than the wait can pass, and the alert can arm, while the wait still blocks the next fire. A window longer than the wait can outlast the wait, and the alert still does not fire until a full window has passed or the ratio has dropped under half.
The event line names the coin and says volume is that multiple of its 20-day average. That line is the ratio that fired. It is not a rating of the coin.
It is not an unusual move
An unusual move uses the same windows, 15 minutes, 1 hour, 4 hours, or 24 hours, and the same 1-hour default. It does not use volume. It compares the price change with that coin's usual price change, times a multiple. The default multiple is 3, the range is 2 to 6, and the bar is never under 0.5%. The usual wait is 4 hours, not the 1 hour a volume spike uses.
The unusual-move page walks through that price comparison. A volume spike can fire without a large price move, and an unusual move can fire without a volume spike. Neither one says what the next price will do. A missing volume is never read as zero. If the window is too gappy, or the history is too short, the check has no answer and does not fire.
Terminal states the multiple, the window, and the 20-day average on the alert, and it treats a volume spike as a volume record rather than a recommendation.
FAQ
Is 3× the same event on every coin?
No. 3× means three times that coin's own average volume per minute over the prior 20 days. Two coins with the same multiple can have very different averages.
What if some minutes in the window are missing?
They are left out of both sides. They are not treated as zero. The check needs at least 90% of the window. Below that, it does not fire.
Why can heavy trading still not fire?
The history may be under 10 days (14,400 minutes). Volume times price may be under $10,000. Or the ratio may be under your multiple. A missing volume is not filled in.
Sources. The figures on this page are the product's volume rules. They are not a live print of any coin.