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Author Topic: magnetic disturbance before earthquakes  (Read 2208 times)

KC6RWI

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magnetic disturbance before earthquakes
« on: January 17, 2019, 10:31:14 AM »

Just some wikipedia I found about the Loma Prieta quake in 1989. Sadly others dismissed the findings over bad sensors, I wonder.

After the 1989 Loma Prieta earthquake occurred, a group led by Antony C. Fraser-Smith of Stanford University reported that the event was preceded by disturbances in background magnetic field noise as measured by a sensor placed in Corralitos, about 4.5 miles (7 km) from the epicenter. From October 5, they reported that a substantial increase in noise was measured in the frequency range 0.01–10 Hz. The measurement instrument was a single-axis search-coil magnetometer that was being used for low frequency research. Precursor increases of noise apparently started a few days before the earthquake, with noise in the range 0.01–0.5 Hz rising to exceptionally high levels about three hours before the earthquake. Though this pattern gave scientists new ideas for research into potential precursors to earthquakes, and the Fraser-Smith et al. report remains one of the most frequently cited examples of a specific earthquake precursor, more recent studies have cast doubt on the connection, attributing the Corralitos signals to either unrelated magnetic disturbance or, even more simply, to sensor-system malfunction.
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KA0HCP

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RE: magnetic disturbance before earthquakes
« Reply #1 on: January 19, 2019, 08:09:52 PM »

No, the report was not dismissed over faulty sensors.  After almost 30 years, no corroborating findings have been made.  Faulty sensors are simply the most reasonable explanation.
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KA0HCP, ex-KB4QAA Relocated to Ks. April 2019.

K1JRF

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RE: magnetic disturbance before earthquakes
« Reply #2 on: April 26, 2019, 11:45:07 AM »

Sorry for the late post but just found this post....apologies to those that go apoplectic over necro threads....:)
I wanted to share my experience with predicting earthquakes and with the Loma Prieta one in particular.
I'm a New Englander with little prior earthquake experience but was living near Santa Cruz for a 4 month stint while being trained by a new employer.
My wife and I rented a house in Capitola and due to the long duration of our stay we brought out cat, Frank Zappa, out there with us. (He had a white face with a black mustache and goatee that reminded me of Zappa)
One night we could not find the cat and when I went looking for him he was hiding under the bathroom sink so I just thought he was having a "I'm in a strange house moment" so I grabbed him and brought him to the living room to be with my bride and I while we watched a movie and shortly he was gone again. And yup he was back hiding under the sink. I left him there and when I got back to the living room there was a sharp "snap" type feeling and sound. I looked at my wife and said "hmm house settling" but with her being from Taiwan and experienced with earthquakes she said "nope welcome to your first earthquake"! So that was that, no damage in that area and we joked about the cat sensing the earthquake.
Fast forward several years later and we are living in Vermont south of Burlington and one night I could not find the cat and located him under the , yup you guessed it, the bathroom sink! Both houses had one of those pedestal style sinks with the curtain like wrap around it if you are trying to picture this. So I grabbed him and he ran right back there. I joked with my wife about "oh no there's going to be an earthquake" and we forgot about it and went to bed. The next day when I got the newspaper (yes before the internet) it had a headline about an earthquake up north a bit near Montreal and how it was felt by peeps in Burlington etc. If I remember right it was only around a 3.5 or so.  We didn't feel it ourselves but after those two incidents we were both convinced this cat could somehow sense something before it happened earthquake wise. It was only on those two occasions in his 18 year life of tormenting me that we ever saw that type of behavior out of him.
So sensors blah... get a cat:)
Thanks for reading if you got this far..... Happy DX
John K1JRF
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KD6IWD

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RE: magnetic disturbance before earthquakes
« Reply #3 on: May 14, 2019, 01:42:10 PM »

Here in Texas I know a geologist who was conducting a magnetotelluric survey the day of the big Mexico city earthquake. The signals on the 0-300 hertz magnetotelluric survey made detecting signals related to oil and gas un-readable.
They had to quit for that day.
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K0UA

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RE: magnetic disturbance before earthquakes
« Reply #4 on: May 15, 2019, 03:27:58 PM »

Sorry for the late post but just found this post....apologies to those that go apoplectic over necro threads....:)
I wanted to share my experience with predicting earthquakes and with the Loma Prieta one in particular.
I'm a New Englander with little prior earthquake experience but was living near Santa Cruz for a 4 month stint while being trained by a new employer.
My wife and I rented a house in Capitola and due to the long duration of our stay we brought out cat, Frank Zappa, out there with us. (He had a white face with a black mustache and goatee that reminded me of Zappa)
One night we could not find the cat and when I went looking for him he was hiding under the bathroom sink so I just thought he was having a "I'm in a strange house moment" so I grabbed him and brought him to the living room to be with my bride and I while we watched a movie and shortly he was gone again. And yup he was back hiding under the sink. I left him there and when I got back to the living room there was a sharp "snap" type feeling and sound. I looked at my wife and said "hmm house settling" but with her being from Taiwan and experienced with earthquakes she said "nope welcome to your first earthquake"! So that was that, no damage in that area and we joked about the cat sensing the earthquake.
Fast forward several years later and we are living in Vermont south of Burlington and one night I could not find the cat and located him under the , yup you guessed it, the bathroom sink! Both houses had one of those pedestal style sinks with the curtain like wrap around it if you are trying to picture this. So I grabbed him and he ran right back there. I joked with my wife about "oh no there's going to be an earthquake" and we forgot about it and went to bed. The next day when I got the newspaper (yes before the internet) it had a headline about an earthquake up north a bit near Montreal and how it was felt by peeps in Burlington etc. If I remember right it was only around a 3.5 or so.  We didn't feel it ourselves but after those two incidents we were both convinced this cat could somehow sense something before it happened earthquake wise. It was only on those two occasions in his 18 year life of tormenting me that we ever saw that type of behavior out of him.
So sensors blah... get a cat:)
Thanks for reading if you got this far..... Happy DX
John K1JRF

Yours would not be the first account of earthquake detection by animals.
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73  James K0UA
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