太空天文與電漿科學研究所
Institute of Space, Astrophysical and Plasma Sciences
Observations of ELF-Emissions and
Their Correlations with Large Earthquakes
in Taiwan
演講者：汪愷悌 博士
單 位：成功大學電漿所/電漿中心
時 間：2010 年 3 月 18 日(四) PM 2:10 ~ 4:00
地 點：電漿所 64115 室
A total number of 178 emission events were detected by the
magnetic field antennas at extremely-low-frequency (ELF) range
below 120Hz at the ELF station of Lulin Observatory in Taiwan
from August of 2003 to July of 2004. In this seminar, I will present
these observational results in two parts.The 1st part will focus on the
features of these emissions and their classification according to event
patterns on the frequency-time spectrograms. The possible
generation mechanisms for these events from the point of view of
space physics will also be discussed. The 2nd part will emphasize
the statistical analysis results for these observations from another
point of view, that is to say, their association with magnitude (M)≧5
earthquakes occurred in Taiwan. The results based on twenty large
earthquakes show that the occurrence rate of the ELF-emission
events are enhanced above the average around 5 to 7 days before the
earthquakes occur.The extent of occurrence rate is also found to be
different for three different epicenter regions: Central Mountain,
Coastal to Luzon Arc, Okinawa.Trough, Ryukyu Arc, to Philippine
Sea. Further detail analysis suggests that these occurrence rates can
also correlate with M/r or M/r2, where M is the earthquake
magnitude and r is the distance from the epicenter to Lulin station.
Finally, previous studies on the electromagnetic signals associated
with earthquakes will be reviewed and future direction for this topic
will be discussed.
歡迎老師同學出席!