Tracking Magma at Alaskan Volcanoes: 2005 - 2011

1. Tracking Magma at Alaskan Volcanoes: 2005 - 2011 J.A. Power, S. G. Prejean, S.D. Stihler, Z. Lu, C.J. Nye, D.J. Schneider, J.T. Freymueller, P.F. Cervelli, S.R. McNutt.

2. Organization: Alaskan Volcanic Centers • Aleutian Arc Volcanoes • AVO Monitoring • Communication • Recent Unrest/Eruptions • Spurr (2005) • Kastochi (2008) • Augustine (2006) • Redoubt (2009) • Okmok (2008) • Pavlof (2007) • Summary Spurr Redoubt Pavlof Okmok Kasatochi Augustine

3. Alaska Volcano Observatory Monitoring Seismic Stations in Alaska • Monitoring Techniques • Seismology • Continuous GPS • Remote Sensing (visual & InSAR) • Webcams • Airborne Gas (SO2 & CO2) • Geology • Pressure • Others Red = AVO, Yellow = AEIC, Purple = WCATWC, Black = GSN

4. AVO Volcano Communication • ALASKA VOLCANO OBSERVATORY • ALASKA DEPARTMENT OF EMERGENCY SERVICES • US AIR FORCE • NOAA/NATIONAL WEATHER SERVICE • FEDERAL AVIATION ADMINISTRATION • Others http://vaac.arh.noaa.gov/interagency_plan.pdf

5. Mount Spurr: 2005 Historical Eruptions 1953 1992 Anchorage Spurr Summit ~6000 Years BP Crater Peak 1953 & 1992 Vent Monitoring Equipment 9 SP Seismometers 3 BB Seismometers 3 CGPS 1 Webcam

6. 2004 - 2006 2004 – 2007 Spurr Seismicity is characterized by: Shallow VTs beneath Spurr Summit. Small magnitudes. Deep Long-Period Events to SE. Changes in stress direction (D. Roman).

7. Gas (CO2) Flux Thermal – Snow Melt Geodesy – CGPS Inflation Yellow: July 26, 2004 – January 12, 2006 Spurr Summit 2005…… Unrest is driven by a deep intrusion marked by DLP and shallow seismicity, snow melt, gas flux, and inflation.

8. Kasatochi Volcano: 2008 VEI 4 Historical Eruptions None No Local Monitoring! Photo by Jerry Morris

9. Korovin Kasatochi Great Sitkin Closest Seismometer ~ 37 km August 6, 2008 August 7, 2008 Evacuation Complete ORANGE M5.6 YELLOW, Evacuation Effort Started RED, First Explosion Explosions

10. GOES Band 4m5: 09 Aug 2008 0100 UTC Ash Cloud on August 9, 2008

11. Kasatochi in retrospect…Successful forecast was possible because of large energy release at a long dormant center. 6 Kasatochi area seismicity from the AEIC earthquake catalog 4 Earthquake Magnitude 2 March April May June July August 2008 If the volcano had been seismically monitored, we would have had weeks to months of warning.

12. Aleutian Volcano Seismic Moment 1 fringe = 11.76 cm

13. Augustine Volcano: 2006 VEI 3 Historical Eruptions 1986 1976 1963-64 1935 1882 1812 2006 Monitoring Equipment 9 SP Seismometers 4 BB Seismometers 5 CGPS

14. ORANGE RED 5 days 60 Minutes Augustine…… The 2006 eruption was proceeded by 8 to 9 months of increasing shallow seismicity, Distal VTs, deformation (inflation), and gas flux. This pattern of precursory activity was similar to the 1986 and 1976 eruptions. Fisher et al., 2010

15. Photo by C. Read Redoubt Volcano: 2009 VEI 3 Historical Eruptions 1989-90 1965 – 66 1933 1902 2009 Monitoring Equipment 5 SP Seismometers 5 BB Seismometers (installed 2009) 5 CGPS (4 installed in 2009)

16. Deformation Sulfer Smell Snow Melt • DLP Characteristics • Z ~ 28 – 37 km • ML ~ 0.7 – 1.4 • SEH ~ 0.5 – 2.5 km • SEZ ~ 1.0 – 3.0 km

17. Grapenthin, et al., Submitted Geodetic Observations during the 2009 eruption of Redoubt Volcano, Alaska, JVGR, Submitted. The 2009 eruption was also preceded by a small inflation observed at AC17 ~30 km northeast of the edifice beginning in July 2008 (Grapenthin et al. Submitted).

18. Redoubt 2009 Shallow Precursory Seismicity February 21 – March 23 January 21 – February 20 Orange 30 Days Yellow Orange Red 6 Hours Redoubt 2009 …… The 2009 Eruption was proceeded by marked increases in gas flux, deformation, and Deep Long-Period (DLP) seismicity. Short-term forecasting was difficult because of pervasive tremor and swarms of shallow events – a strong contrast to the 1989-90 activity.

19. Photo by C. Read Okmok Volcano: 2008 VEI 4 Historical Eruptions 1997 1988 1983 1981 + 12 more since 1805 ~9.5 km Monitoring Equipment 6 SP Seismometers 4 BB Seismometers 4 CGPS

20. Eruption Begins 24 Hours RED 30 Minutes

21. 3 2 Earthquake Magnitude 1 0 1 2 3 4 5 6 7 8 9 10 Month in 2008 Okmok in Retrospect: Very short precursors! 6 hours before eruption: No unusual activity (although some CGPS stations are inoperable). No advance warning was issued! Co-eruption signals are strong! Okmok Co-Eruption Signals COLOR CODE: GREEN RED 1 fringe = 2.83 cm Subsidence of >50 cm

22. Pavlof Volcano: 2007 VEI 2 Historical Eruptions 1996-97 1988 1986 1983 1981 + 34 since 1790 Monitoring Equipment 6 SP Seismometers Aeromap 1996

23. Yellow 3 days Strombolian Eruption Reported Orange 1 Hour Neither the 2007 or 1996-97 eruptions show deformation in InSAR, however, CGPS data is not available. Pavlof in retrospect… Frequently active or open-vent system that exhibits very mild precursory activity.

24. Summary • Kastatochi and Spurr suggest long dormant vents activate over months to years. • Long dormant vents and flank intrusions can involve large release of seismic energy. • Aleutian events suggest deformation (CGPS & InSAR) and DLP seismic events hold promise for extending forecasting window. • Frequently active centers (Okmok & Pavlof) can activate much faster and with very weak short-lived precursors.