Strong M7.8 from Alaska disrupts shortwave radio

Discussion in 'Ham Radio Discussions' started by VE7DXW, Jul 22, 2020.

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  1. W7UUU

    W7UUU Principal Moderator Lifetime Member 133 Administrator Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    You are not correct.

    Please check which forum this thread is in.

    WR2E and KA2FIR like this.
  2. WZ7U

    WZ7U Ham Member QRZ Page

    I dislike being the fly in the ointment around here sometimes, but while the redirect is functioning the thread is still prominent on the top of the news page. FYI ;)
    N3FAA likes this.
  3. W7UUU

    W7UUU Principal Moderator Lifetime Member 133 Administrator Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    That's been pointed out. I'm guessing there is some lag time before the QRZ Home Page catches up to the Xenforo Forum Software. Remember that this forum software is hosted by as a site where it lives, and then feeds data from key forums back to the home page "Hollywood Squares" announcements. I do not believe they are linked in absolute real time however and it likely will take some time for the home page feed to match up with the Xenforo postings and where this thread now resides (Ham Radio Discussions).

    Thread was moved yesterday by Fred AA7BQ after he realized it was approved into the wrong forum in the first place.

    Tempest in a teapot. Give it some time

    WZ7U likes this.
  4. WZ7U

    WZ7U Ham Member QRZ Page

    Ok, but I can get here from there still. Tomorrow might be a different story.

    You're right though, much ado about nothing.

    But, still a good hit generator. Again. :D
  5. K0RGR

    K0RGR Premium Subscriber QRZ Page

    OK, but I have to ask the question - was anyone listening on the HF bands to signals passing over the quake zone before, during, or after the event? Perhaps signals from Asia to the midwest or east coast? If so, did you observe any unusual effects on those signals?

    Yes, I once observed what I believe was an earthquake precursor. My father observed three of them in his long life of nightly radio listening, and he shared one with me. One of his was the Alaska quake of 1964.

    The one he showed me was in the LA Basin, and signals in the SF Bay Area from that region were distorted with what sounded like the echo from trans-auroral signals. Correspondence I've had with scientists reveal that the current theory involves gravity waves causing ripples in the ionosphere, creating Doppler shifts like the aurora. The effect was observed on all bands from 160-20 meters.
    Similar effects have been reported many times on many large quakes. Smaller quakes do not seem to produce the effect.
  6. VE7DXW

    VE7DXW XML Subscriber QRZ Page

    As the quakes wind up and the pressure of the plate increases, the piezo electric charge and current builds up. This sends magnetic field-lines into sky, which disrupt the ionosphere and the existing propagation long before the quake breaks. This process has been confirmed by many experiments over time and we have this recorded on several 100 quakes over the years. It is a very common occurrence. It makes sense that the quakes have buildup and do not release out of the blue.
    Because we utilize every available station in the world that sends radio waves to the RF-Seismograph, reflected via the ionosphere and 6 bands, the chances to get a pass that goes over a quake is enhanced. Alex
    KA4DPO likes this.
  7. W1PJE

    W1PJE Ham Member QRZ Page

    What is the amplitude of the magnetic disturbance you theorize? How does it quantitatively compare to the background terrestrial magnetic field, whose value ranges from 30,000 nT to 50,000 nT depending on location? That kind of quantitative comparison is required to gauge whether the magnetic disturbance is significant enough to affect ionospheric refraction, as codified in the Appleton-Hartree magneto ionic propagation equations.
    KA4DPO and VE7DXW like this.
  8. K8DO

    K8DO Ham Member QRZ Page

    Animals have been known from antiquity to change their behavior before earthquakes occurred.
    AS far as ionospheric changes in propagation from seismic activity:
    1. We can hypothesize that low frequency, very low amplitude vertical motion (breathing) of the sub-crustal regions before the quake - where the crust finally slips (subducts) - occurs and mechanically couples to the ionosphere by slowly bouncing the floor that the air mass stands on, causing waves passing through the ionosphere (depressing the bottom of a thin pan of still water)
    2. We can hypothesize that minor alterations in the flow of the melted earth core ( as the sub-crustal region deforms in a local area under the increasing stress of the crust as it gets ready to slip) will couple electromagnetically to the ionosphere disrupting the layers and thus propagation.
    3. Or we can hypothesize that the deforming of the crust electromagnetically couples directly to the active layer of the ionosphere.
    KA4DPO likes this.
  9. W1PJE

    W1PJE Ham Member QRZ Page

    Certainly all possibilities. It's a pretty ill-defined space in that many mechanisms could exist - but which ones do, and in what relative strength? With the question above yours, we're trying to put some values on the delta B disturbance, because the original claim here is that HF propagation is markedly affected. That has definite implications in the refraction formulas and these implications either work or they don't - but numbers are needed. For example, if the disturbance is say 1 nT out of a 30,000 nT background, this would not change refraction noticeably at all. (Essentially, a change in |B| would affect the electron gyro frequency and its harmonics, which are central portions of the refraction equation.)–Hartree_equation
  10. WA1GXC

    WA1GXC Ham Member QRZ Page

    Time Now Thursday night / Friday 0217Z home page:
    Array of promo stories

    Matrix at top of page -- Row of 3 features

    Left:"Featured Member" a PY ham

    Center window; Tagged "QRZ News" "Strong M7.8 From Alaska Disrupts Shortwave Radio"

    Right window: customary propagation data

    Presented as factual--"QRZ News"-- and the commenter's observation is self-evidently accurate as presented.

    Confusing, and maybe merits review.

    Last edited: Jul 24, 2020
    N3FAA likes this.
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