Dr. Lucy JonesOvjeren akaunt

@DrLucyJones

Seismologist, Founder & Chief Scientist of , Author of The Big Ones (Doubleday), Viol Player. I only accept media requests thru my website.

Southern California
Vrijeme pridruživanja: ožujak 2014.

Tweetovi

Blokirali ste korisnika/cu @DrLucyJones

Jeste li sigurni da želite vidjeti te tweetove? Time nećete deblokirati korisnika/cu @DrLucyJones

  1. Prikvačeni tweet

    The potential for increased weather disasters coming with climate change make the earthquake problem look small. My music on the data of the changing climate: In Nomine Terra Calens: In the name of a warming Earth via

    Poništi
  2. Poništi
  3. Natural hazards are inevitable but natural disasters are not. Some of my thoughts about why resilience is important and how we get there. via

    Poništi
  4. The fault orientation and type forms the pattern of seismic waves radiated by the quake and recorded at many stations. We calculate a moment tensor that matches that pattern, so can see the fault within ~15 min.

    Poništi
  5. proslijedio/la je Tweet
    28. sij
    Odgovor korisnicima

    The rate of large earthquakes right now is totally ordinary, geologically. The happenstance of a few in more populated areas means we've seen a little more media reporting, plus once you start noticing them, it's hard to stop!

    Poništi
  6. The Jamaican M7.7 is not related to the Puerto Rican quake. Triggering of another quake happens within ~3x length of the 1st fault. The PR quake was on a ~15 mile long fault, but the M7.7 was over 800 miles away. Way too far away to be related.

    Poništi
  7. The M6.5 near the Caymans is almost certainly an aftershock of the M7.7. The M7.7 fault should be 100+ miles long - aftershocks show which way the fault runs from the mainshock. This map shows the Cayman event is ~120 miles down the Oriente fault from the M7.7

    Poništi
  8. 6 of 6: Today's Jamaican quake is strike-slip & did not produce a tsunami. Because there is no tsunami at the source, there cannot be a tsunami showing up somewhere else (like the US)

    Prikaži ovu nit
    Poništi
  9. 5 of 6: Tsunami waves move fast ~450 mi/hr. Faults near shore produce tsunamis that can arrive in a few minutes to 10s of minutes after you feel strong shaking. Time to go up hill. Tsunamis come in a series of waves that can last for a day. The first wave may not be the biggest

    Prikaži ovu nit
    Poništi
  10. 4 of 6: Strike-slip faults (faults that move the ground sideways, not vertically), like Jamaica, do not cause tsunamis b/c they do not change height of the seafloor. They can cause a local tsunami by triggering underwater landslides.

    Prikaži ovu nit
    Poništi
  11. 3 of 6: The 2 main causes of tsunamis are quakes on faults that push up seafloor & landslides. How big a tsunami is = how much water is displaced = how much seafloor moves up by how much. Only the biggest quakes (M≥8.5) move enough water to create a tsunami that crosses ocean

    Prikaži ovu nit
    Poništi
  12. 2 of 6: Tsunamis get taller when they approach shore. The whole column of seawater above a fault is moved, so there is a lot of water & energy in the wave, more if the sea is deeper at the source. As it approaches shore & depth of sea decreases, the height of the wave increases.

    Prikaži ovu nit
    Poništi
  13. A tsunami primer (1 of 6): Tsunamis begin when the shape of the seafloor changes suddenly. The water above the changed seafloor is pushed up, but then because it is a fluid, immediately falls down to both sides, creating the wave that moves towards shore

    Prikaži ovu nit
    Poništi
  14. The M7.7 Jamaican quake produced sideways motion on the fault, so the tsunami risk is low. (Seafloor should move up to make tsunami.) But if I'm ever at the beach and feel strong shaking, I move to high ground. Downside is I lose a day at the beach. The upside could be my life.

    Poništi
  15. A M7.7 has been reported northwest of Jamaica. It appears to be the transform fault boundary between the North American and Caribbean plates.

    Poništi
  16. proslijedio/la je Tweet
    25. sij

    When you want to make a pattern out of a group of , remember that earthquakes happen all the time, and we need statistics to tell us if our pattern is just coincidence. Just because we want a pattern doesn’t make the pattern real.

    Poništi
  17. I sure wish I could tell when a quake is going to be a foreshock. I spent many years looking at foreshocks to try to find something that made them different. Never found it. We will know if it's one of the 5% that become a foreshock if something bigger happens.

    Prikaži ovu nit
    Poništi
  18. Tonight's quake more scientifically interesting. M4.6 north of Barstow, ~halfway between 2019 Ridgecrest and 1992 Landers faults. 1947 M6.5 Manix quake was ~30 miles east of tonight's quake. Occurred on an unmapped thrust fault. Only Barstow seems to care

    Prikaži ovu nit
    Poništi
  19. In the last 11 yrs, USGS recorded 1496 M≥6 events, 1 every 2.7 days. The first 25 days of January 2020 had 10 quakes M≥6. Almost exactly the average of the last 11 years. So, no. I don't see an increase. You can look yourself at

    Poništi
  20. 3. A M3 happens many miles below the surface on a fault a few meters across. No way to connect them with any mapped fault. 4. Foreshocks look like any other quake. We only know it's a foreshock when something bigger happens. Then I can wake up.

    Prikaži ovu nit
    Poništi
  21. (1 of 2)Why you should not expect me to get up in the middle of the night for a M3+ quake: 1. A M3+ happens in SoCal a few times per week. I sleep 8 hr/day so I'd be disrupting my sleep ~1/wk 2. There's nothing interesting about another M3. They happen every week.

    Prikaži ovu nit
    Poništi

Čini se da učitavanje traje već neko vrijeme.

Twitter je možda preopterećen ili ima kratkotrajnih poteškoća u radu. Pokušajte ponovno ili potražite dodatne informacije u odjeljku Status Twittera.

    Možda bi vam se svidjelo i ovo:

    ·