Earthquakes

The funnest part of having a seismometer is looking at the traces of the earthquakes it detects. This page displays some of the more interesting quakes I have detected.

This first earthquake hit off the coast of Nazca, Peru, on November 12, 1996. It was a magnitude 7.3 - quite a large earthquake. This picture is an hour and a half wide. Although this earthquake was over 4,000 miles away, it registered very strongly. This earthquake did quite a bit of damage.

I have converted this waveform into an audio file so that you can hear what an earthquake would sound like if you ears could pick up the extremely low frequencies it puts out. The playback of this file has been speeded up 8,000 times, but otherwise unprocessed. Click for [WAV] or [AU] format.

This next earthquake hit near Vancouver Island, British Columbia, Canada (about 1250 miles away) on October 6, 1996. This was an exciting quake for me because it was the first major earthquake I received with my seismometer. It was a 6.3, still a large earthquake, but not as powerful as the one above. I did not hear any mention of it on the news, so I assume that it did not do any significant damage. This view is half an hour wide.

Next, I present the trace of the biggest, closest earthquake I have recieved so far. It hit on November 27, 1996 with a magnitude of 5.3 near Little Lake, California, 226 miles from me. This is a very sparsely populated area, and as such did not make the news. This view is only ten minutes wide - the quake was over very quickly.

However, few earthquakes are as big as these. The smaller the magnitude, the more frequently they occur. Whereas a magnitude 7 quake occurs maybe only once a month in the world, hundreds of magnitude 2's occur in one day. Below is a smaller, more typical quake. It was a 2.8 that also hit on November 27, 1996, just east of Desert Hot Springs, California. As you can see, it is a little bugger that barely made it above the background noise. This quake was only 88 miles away. The seismometer only shook for about 30 seconds of this ten minute wide view.

Finally, I present the trace of an earthquake that I felt. This one was a magnitude 3.8 that hit on December 28, 1996. The epicenter was near Hemet, California, about 65 miles from me. I was sitting at my computer, typing, when I felt my desk quiver. I felt only a slight motion in my chair. The shaking lasted, oh, maybe three seconds. On the Mercalli intensity scale this would be about a II. Immediately upon feeling the shaking I knew that it was an earthquake, (I have been in several earthquakes before, including the '92 Landers one and the '94 Northridge quake) and turned my head around to look at the output from my seismometer. What is interesting is that while the ground was shaking nothing registered on the seismometer. About three seconds after the shaking stopped, the seismometer began to show the effects. I attribute this lag to the fact that I have a long-period seismometer, which is insensitive to the quick motions of a nearby earthquake. It only registered the slower traveling, long period waves that followed.

From here, you can go back to the main quake page, or go to my home page.

Comments? Questions? Click here to send email to me, Fred Bruenjes.