Ambient Seismic Noise Characteristics in Greenland and the Surrounding Area

Abstract

Greenland as the biggest island in the world has an essential role in the global warming research The ice covers almost 80 % of Greenland’s surface and it is the second biggest ice on earth after Antarctica If all the ice on Greenland melted it will cause the rising of sea level in the world by 7 meters We study the ambient seismic noise in Greenland and the surrounding area by using the probability density function – power spectral density (PDF-PSD) method We have processed 34 seismic recording data during 2016 to 2017 for the Z component into PSD and spectrogram From this PSD and spectrogram we can divide the result into the short period band (0 1 – 1 s) secondary microseism band (3 – 10 s) and primary microseism band (10 – 20 s) The secondary microseism band shows a seasonal variation for each station with the highest power level we can find on the winter season with a peak in February however the lowest power we could see on summer with a peak in July or August We classify the PSD level for each station into four clusters one cluster for the secondary microseism band has a peak at 5 second and the other clusters have a maximum value of 4 -5 second The primary microseism level for all the clusters have a similar pattern with the highest value at 15 seconds The short period band for every cluster has a different level with the period at 0 3 – 0 4 second where cluster 1 has -152 dB cluster 2 has – 138 dB cluster 3 has -145 dB and cluster 4 has -123 dB respectively As we can see the period (3 – 10 s) band is related to the climate system in Greenland almost all the stations at cluster 1 located in arctic climate zone and the other clusters located in sub-arctic climate zone We found that all seismic stations which are located in the central part of Greenland it showed two peaks of secondary microseism almost the whole year On the other hand most seismic stations located on the east and west part showed the two peaks of secondary microseism only for two until four months This means the stations located in central part of Greenland has a different source of secondary microseism for a whole year Due to this problem the investigation was conducted to study the factors which work on secondary microseism in Greenland including the location of the source of secondary microseism band This study will also learn the connection between microseism band and climate systems in Greenland

Date of Award	2018 Aug 20
Original language	English
Supervisor	Ruey-Juin Rau (Supervisor)