Comparison of the Microseismic Signature of Hurricanes Katrina (2005) and Ioke (2006)

In 2006, Hurricane Ioke was the strongest hurricane in recorded history to form in the Central Pacific Ocean. Developing on 20 August 2006 and dissipating on 6 September 2006, Hurricane Ioke was long-lived. It reached the category 5 stage several times and became a super-typhoon after crossing the international dateline. Ioke brushed Wake Island on 31 August 2006 and caused damage on the island estimated at nearly 90 million (2006). We set Hurricane Ioke in stark contrast with Hurricane Katrina, which, nearly exactly one year earlier, crossed Florida before making landfall in Louisiana on 29 August 2005. Katrina caused over 1800 fatalities, and damage was estimated at over 80 billion (2005). With a live span of a week, Hurricane Katrina was much shorter-lived than Hurricane Ioke. Here, we compare the seismic signature of these two storms in the microseism band. Nearby recording instruments were limited for Hurricane Katrina, but for Hurricane Ioke, we utilize the large dataset of the Hawaiian PLUME project (Laske et al., 2009). With over 80 stations, the network of this experiment provided data from 70 ocean bottom seismometer (OBS) sites. In the relatively few records of land seismic stations, the seismic signal of Hurricane Katrina peaked when it made landfall in Louisiana. In contrast to this, the seismic signal of Hurricane Ioke build up as it developed in the open ocean. It peaked when Ioke became a category 5 storm, long before it brushed Wake Island. The large number of OBS sites also allows up to observe marked differences in how the microseismic energy traveled from the hurricane to the seismic network. Finally, with the aid of the significant wave height plots provided by the Fleet Numerical Meteorology and Oceanography Center (FNMOC), we can identify other signals in our microseism records. References: Laske, G., Collins, J.A., Wolfe, C.J., Solomon, S.C., Detrick, R.S., Orcutt, J.A., Bercovici, D. and Hauri, E.H., 2009. Probing The Hawaiian Hot Spot With New Ocean Bottom Instruments, EOS Trans. AGU, 90, 362-363.