At 4:54PM Mountain Time October 25, 2018 (22:54UTC October 25, 2018) a very large M6.8 earthquake struck off the southern coast of Greece. It was very shallow for an earthquake of this magnitude so it really shook up Greece! This area is seismically active and does have large earthquakes from time to time. The largest was apparently a 7.3 on October 6, 1947. However what is interesting with this earthquake is that there was a smaller foreshock just before the 6.8. Also, about 3 hours later, a magnitude 2.9 earthquake struck Montana just about 20 miles northwest of Bozeman. I will show the helicorders first and then the seismogram/spectrogram plots for these different events. PLEASE CLICK THE TITLE OF THIS POST OR "READ MORE" TO CONTINUE!!!
M6.8 in Greece:
Hey guys! So first I am going to talk about the M6.8 earthquake that struck Greece and then I will move on to the M2.9 quake in Montana. On October 25, 2018 at 22:54UTC a very large M6.8 earthquake struck off the coast of Greece. As you will see in the image below, you can see the earthquake was preceded by one foreshock. A foreshock is like an aftershock except it occurs prior to the main earthquake, rather than after. A great example of foreshocks is the Japan 2011 mega-quake. It is well known that there were many foreshocks before that devastating quake.
After the 6.8, over a dozen aftershocks occurred with many more still occurring. It was quite strong! The depth of this M6.8 was 14.0km which is quite shallow for an earthquake of this magnitude. Now I will show you the helicorder for seismic station KEK which resides in the HL network in Greece.
Now I will quickly show two seismogram/spectrogram plots. As always, please pay attention to time period, frequency range, and amplitude count! Remember chart labels are very important and must always be read first before reading any data.
M2.9 Earthquake in Montana:
About 3 hours or so after the M6.8 occurred in Greece, a strong M2.9 earthquake struck about 20 miles northwest of Bozeman, Montana at a shallow depth of 1.0km! Personally I believe it was more like a 3.2 earthquake. Below I will show the location of the earthquake in regards to the two closest seismic stations, the helicorder for the closest seismic station (which would be station SXM), and the seismogram/spectrogram plot. Once again, I cannot stress it enough, you must pay attention to all chart labels first! Also pay attention to time period, frequency range, amplitude count, or any image captions you may see!
*Seismogram/spectrogram plots were generated using data obtained from IRIS and the MB network through the program SWARM from station SXM.
Well that is it for now! Remember generating these images using data obtained from IRIS, and using the program SWARM, is ridiculously easy. It takes a few days to get the hang of, but once you figure it out you realize it is the best way to monitor seismic activity. Feel free to peruse my website here to discover the many different ways to monitor seismic activity. All of what I have learned, in regards to downloading/finding seismic data and analyzing it, has been put here on this website in many different pages. This is done to help others realize just how easy it is to do the things I am doing! Keep your eyes out for more blog posts. Thank you for your time and God bless!
Ben Ferraiuolo is a fast learner and someone who will always stand for the truth. Visit "About Me" for more!