Norman EQ

  1. What magnitude was the Oklahoma Earthquake?
    4.3 (Mw) moment magnitude per USGS

    5.1 magnitude (mbLg) by Oklahoma Geological Survey
  2. Why is there discrepancy between measurements of the Norman earthquake?
    Different measurement surveys, USGS vs. Oklahoma Geological Survey
  3. Nst
    Number of seismic stations which reported P- and S-arrival times for the EQ
  4. Nph
    Number of P- and S-arrival time observations used to compute the hypocenter location
  5. Dmin
    Horizontal distance from the epicenter to the nearest station (in km)
  6. Rmss
    The root-mean-square (RMS) travel time residual, in sec
  7. Gp
    The largest azimuthal gap between azimuthally adjacent stations (in degrees)
  8. M-type
    Magnitude type
  9. Moment (mW)
    Based on the moment of the EQ. Rigidity of the Earth times the average amount of slip on the fault times the amount of fault area that slipped
  10. Date and time of the EQ (epicenter)
    October 13, 2010. 9:06am
  11. Epicenter location distance from Norman
    10 miles East
  12. Epicenter =
  13. Hypocenter =
  14. Epicenter definition
    the point on the Earth's surface vertically above the hypocenter
  15. Hypocenter definition
    the point in the crust where a seismic rupture actually occurs
  16. Area of the earth from angular distances of ___ to ___ degrees from a given EQ that does not receive any direct ____ waves
    P-wave shadow zone; 103, 144, P.
  17. The shadow zone results from
    S waves being stopped entirely by the liquid core and P waves being bent (refracted) by the liquid core
  18. Shadow zone - S-waves being
    stopped entirely by the liquid core
  19. Shadow zone - P-waves being
    bent (refracted) by the liquid core
  20. EQs near OKC
    Jones Earthquake Swarm area
  21. Location of greatest number of EQs in OK
    Eastern Oklahoma county, near Jones, OK
  22. Largest EQ in Oklahoma
    • Magnitude 5.5 (intensity XII)
    • Occurred April 9, 1952
    • centered near El Reno
  23. Largest OK earthquake caused by slippage along
    Nemaha fault
  24. Second largest earthquake in OK magnitude and location
    Magnitude 4.6, near Wewoka
  25. Third largest earthquake in OK magnitude and location
    4.3 magnitude, 10 miles east of Norman
  26. Is there any obvious reasons why the earthquake was located there?
    Oklahoma basins
  27. Rock age at hypocenter of OK EQ
  28. mathematical device to compare the size of earthquakes
    Richter scale
  29. The magnitude from an earthquake is determined from
    the logarithm of the amplitude of waves recorded by seismographs
  30. Because of the logarithmic basis of the scale, each whole number increase in magnitude represents
    a tenfold increase in measured amplitude
  31. Difference in measured energy between each whole number on the Richter scale
    31 times more energy than previous whole number
  32. Earthquakes with magnitude 2.0 or less called
  33. Great earthquakes have magnitude of
    8 or greater
  34. True of false: The Richter scale has no upper limit.
  35. Another scale devised for more precise study of great earthquakes
    moment magnitude scale
  36. True of false: the Richter scale is used to express damage.
  37. An estimate of the energy release or size of an earthquake
    Magnitude (M)
  38. ________ a measure of the size of the earthquake.

    ________ is the level of ground shaking at a specific location

  39. Earthquake Magnitude - Various Scales

    local magnitude consistent with the magnitude of Richter
  40. Earthquake Magnitude - Various Scales

    Moment Magnitude
  41. Earthquake Magnitude - Various Scales

    teleseismic surface-wave magnitudes at period of ~ 20 sec
  42. Earthquake Magnitude - Various Scales

    regional Lg magnitude measured in a narrow period range around 1s

    determined from 1.0 hertz S waves
  43. Magnitude (M) is controlled by
    the fault length (or area) that ruptures
  44. What controls the level of shaking in an earthquake?
    Magnitude -more energy released

    Distance -shaking decays with distance

    Local soils -amplify the shaking
  45. Bigger earthquakes last a _____ time
  46. MMI =
    Modified Mercalli Intensity
  47. Largest recorded earthquake in the world was a magnitude ___ located in ___ on _____.
    9.5, Chile, May 22, 1960
  48. Largest recorded earthquake in the US magnitude ____ in _____ on _____.
    9.2, Alaska, Good Friday, 1964
  49. How many detectable earthquakes in the world each year?
  50. Most earthquake waves have a frequency of
    less than 20 Hz
  51. In the US, which two states have the smallest number of earthquakes?
    Florida and North Dakota
  52. Mid Continent Rift and New Madrid Area contain two types of faults
    strike slip

    reverse fault
Card Set
Norman EQ