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"
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Last events 10 km from summit

Mag Time (Local) (UTC) Depth (Km) (Miles)

Mount Jefferson is a stratovolcano, and the second highest peak in Oregon State. It is located 169 km E of Corvallis, OR.

Details regarding eruptive events at Mount Jefferson are poorly known for several reasons. The last major eruption occurred around 7,600 years ago, and since that time the volcano has been covered by large glaciers that have eroded away many deposits. Mount Jefferson has a history that extends back for several hundred thousand years, and it has exhibited a wide range of eruptive styles from highly explosive events to lava flows and lava domes.

More background information on Mount Jefferson

Background Seismicity

The PNSN operates 1 seismometer near Mount Jefferson. On average, we locate 0 earthquakes within 10 km of the volcano per decade.