and the next day another explosive eruption sent ash into the atmosphere. This explosion created a 20–30 meter wide crater in the new lava dome. On September 22, 2007, the Alaska Volcano Observatory reported that shallow earthquake activity had increased over the week of September 22. However, the activity was less than its level during the months leading up to the 2005–2006 eruption. Sensor networks The Plate Boundary Observatory has a network of 10 high-precision GPS instruments on the flanks of Augustine. Subsequent volcanic activity claimed two of those sites. The Alaska Volcano Observatory also operates a number of seismometers and tiltmeters all around the volcano, including four webcams. See also List of volcanoes in the United States References Notes Further reading Kienle, Jürgen, Zygmunt Kowalik, and T. S. Murty. "Tsunamis Generated by Eruptions from Mount St. Augustine Volcano, Alaska." Science 236, no. 4807 (1987): 1442–447. http://www.jstor.org/stable/1699705. External links Augustine activity Augustine Volcano Live Webcam NASA Images from December 2005 1986 in Alaska 1994 in Alaska 2006 in Alaska 20th-century volcanic events 21st-century volcanic events Active volcanoes Complex volcanoes Islands of Alaska Mountains of Kenai Peninsula Borough, Alaska Lava domes Mountains of Alaska Stratovolcanoes of the United States Volcanoes of Alaska