Aftershock activity of the great 1998 earthquake in the Antarctic plate

• Main Authors: Katsutada Kaminuma, Reiji Kobayashi, Yoshifumi Nogi, Masaki Kanao
• Format: Report
• Language: English
• Published: National Institute of Polar Research/National Institute of Polar Research/National Institute of Polar Research/National Institute of Polar Research 1999
• Subjects: Antarctic earthquake; aftershock; b-value; p-value; intraplate earthquake; Antarctic; The Antarctic; Balleny Islands; Antarc*; Polar geoscience
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=3051; http://id.nii.ac.jp/1291/00003051/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=3051&item_no=1&attribute_id=18&file_no=1

On March 25, 1998, a great earthquake (M_s 8.0) struck the Balleny Islands region. This intraplate earthquake is the largest ever recorded in the Antarctic plate where the seismicity is very low. The aftershock activity of the Antarctic earthquake is investigated using the Weekly PDE (Preliminary Determination of Epicenters) seismicity catalog. Sixty seven aftershocks have been located during a period of 273 days. The distribution of the aftershocks may suggest that the fault plane trends E-W. The statistical parameters of the aftershock activity are determined. The b-value of the Gutenberg-Richter magnitude-frequency relation is 1.05. The large b-value indicates that many small aftershocks have occurred. The p-value of the modified Omori formula for aftershock activity is also determined as 1.14. In comparison with other great earthquakes, the p-value is relatively small, which may indicate that the aftershock activity continued for a long time.