Volcano Map Legend

The sizes of symbols scale with earthquake magnitude, and their color with either the age of the earthquake or its depth, as shown in the legend below, and selected in the Control Panel. Clicking on an earthquake symbol shows its basic information and a link to a page with more details about the individual earthquake.


Control Panel

Volcano Map Panel

Using the tools in this panel you can control the earthquakes shown on the map. The minimum magnitude to plot is selected by the slider. The "Time" and "Depth" determines whether earthquake age or depth are used to color the symbol.

Show all magnitudes >

Custom Search


Instructions: Close
Please follow the steps below:
  • 1) To begin, click the "Draw" button
  • 2) Click a point on the map, this will be the left side of the cross-section.
  • 3)Click a second point on the map, this will be the right side of the cross-section.
  • 4) Drag square on line to include events to plot.
    • 5) Select plot type and depth constraint if any.
    • 6) Click "Plot"
A Km B

Last events 10 km from summit

Mag Time (Local) (UTC) Depth (Km) (Miles)
Description (Crater Lake)

Crater Lake is the remnant of a volcano formerly known as Mount Mazama. It is located 97 km NW of Klamath Falls, OR.

From a probable elevation of roughly 12,000 feet, the top of former Mount Mazama was lost to eruption and collapse that left the present caldera and the deepest lake (1,949 feet) in North America. The catastrophic, caldera-forming eruption that occurred 7,700 years ago is the largest known eruption from Cascade Range volcano. Since then, effusive eruptions built the Wizard Island volcano and two others on the caldera floor as Crater Lake filled to its present level. In the most recent known eruption, a small lava dome grew on the flank of the Wizard Island edifice about 4,800 years ago. Crater Lake is still hydrothermally active.

More background information on Crater Lake

Background Seismicity

The Cascades Volcano Observatory and the PNSN cooperatively operate 4 seismometers on or near Crater Lake. On average, we locate 0 to 1 earthquakes within 10 km of the volcano each decade.