Data Services Products: MEQL - Hurricane Issac Microseism Energy Quick Look (MEQL) Highlight - hurricane Issac

Summary

Images on this page represent the integrated median power time series calculated from the power spectral densities (PSDs) for the vertical, N-S and E-W components of selected GSN stations along the path of hurricane Issac (formed on 2012-08-21 & dissipated on 2012-09-03).

Description

IRIS DMC’s Noise Toolkit is used to compute microseism energy (ME) variations at different period bands for selected GSN stations located along the hurricane Issac’s path. These ME values are calculated by integrating the power spectral density (PSD) functions computed from the waveform data of the above stations. The resulting power time histories show variations in stations noise level caused by passage of hurricane Issac.

Image to the right (click for a larger view) shows map of Issac’s path and its wind speeds in blue (data from US Naval Research Laboratory, Marine Meteorology). On this map location of 7 selected GSN seismic stations: CU.ANWB, CU.SDDR, CU.GTBY, IU.DWPF, IU.HKT, IU.WVT & II.SACV (II.SACV was offline during this event) are shown in red.

For each station median microseismic power values are computed for the (BHZ, BH1,BH2) or (BHZ BHN,BHE) channel groups at period bands of 1s to 5s, 5s to 10s & 11s to 30s that correspond to the local microseism (LM), secondary microseism (SM) and the primary microseism (PM) bands respectively. The resulting microseismic power values are smoothed using a moving 6 hour median window. The time span for computations is from 2012-08-19 to 2012-09-06 that covers hurricane Issac (formed on 2012-08-21 & dissipated on 2012-09-03).

The following images (one set per station) show the microseism energy temporal variation of the BHZ and 2 horizontal channels at the selected stations for the period band of 1s to 5s (local microseism, top row), 5s to 10s (secondary microseism, middle row) and 11s to 30s (primary microseism, bottom row). click on each image for a larger view.

II.SACV (no data)

CU.ANWB

local microseism (LM), 1s to 5s
secondary microseism (SM), 5s to 10s
primary microseism (PM), 11s to 30s

CU.SDDR (no data)

CU.GTBY

local microseism (LM), 1s to 5s
secondary microseism (SM), 5s to 10s
primary microseism (PM), 11s to 30s

IU.DWPF

local microseism (LM), 1s to 5s
secondary microseism (SM), 5s to 10s
primary microseism (PM), 11s to 30s

IU.HKT

local microseism (LM), 1s to 5s
secondary microseism (SM), 5s to 10s
primary microseism (PM), 11s to 30s

IU.WVT

local microseism (LM), 1s to 5s
local microseism (LM), 1s to 5s
secondary microseism (SM), 5s to 10s
primary microseism (PM), 11s to 30s

Citations and DOIs

Credits

  • IRIS DMC Products Team

Categories

Tags

MEQL

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