Larsen et al. (2009) EOS

2008 eruption of Okmok

strongtremor

OKWE RSAM

7/13 7/20 7/27 8/03 8/10 8/17

ampl

itude

(arb

. uni

ts)

Okmok eruption seismicity

VLP tremor during Okmok eruption

VLP tremor has been previously reported by De Lauro et al. (2005) at Stromboli

Stations used for tremor analysis

Comparison of Amplitude Spectra

OKSOz-OKFGz inter-station times

Histograms of 10 inter-station times

Tremor located NNW of Cone D

Haney (2010) JGR, in press

new cone Cone D caldera rim

north south

Similar phase velocity for Love waves, so a similar inter-station time expected

Horizontal components

Not similar to ZZ or RR

Sign flip on OKFGt

Radiation pattern for a vertical CLVD

Azimuth constrained by Love waves, source depth by Rayleigh waves

Rayleigh radiation: VLP tremor depth

approx. edge of caldera

Masterlark, Haney, et al. (2010) JGR

Ambient noise tomography of Okmok

Radiation pattern for a vertical CLVD

Haney (2010) JGR, in press