Earthquake warning system

• US 9,372,272 B2
• Filed: 12/19/2011
• Issued: 06/21/2016
• Est. Priority Date: 12/17/2010
• Status: Expired due to Fees

• Current Assignee: Seismic Warning Systems, Inc.
• Original Assignee: Seismic Warning Systems, Inc.
• Inventors: Price, Michael John, Wurman, Gilead
• Primary Examiner(s): Mehmood, Jennifer
• Assistant Examiner(s): Point, Rufus
• Application Number:
  US13/993,394
• Publication Number:
  US 20130328688A1
• Time in Patent Office: 1,646 Days
• Field of Search: 340/690
• US Class Current: 1/1
• CPC Class Codes: G01V 1/01 Measuring or predicting earthquakes
• CPC Class Codes: G01V 2210/1232 Earthquakes
• CPC Class Codes: G01V 2210/65 Source localisation, e.g. faults, hypocenters or reservoirs
• CPC Class Codes: G01V 2210/72 Real-time processing
• CPC Class Codes: G08B 21/10 responsive to calamitous events, e.g. tornados or earthquakes

Abstract

A method or system for detecting a seismic event includes detecting a primary wave of a seismic event using at least one sensor at a measurement location; using at least one parameter of the detected primary wave to determine an estimated peak ground intensity at the measurement location without determining the magnitude of the seismic event; determining an epicenter of the seismic event; and estimating the intensity of the seismic event at a specified location using the determined estimated peak ground intensity and the distance of the specified location from the epicenter. The epicenter can be determined using sensors at a single location. A noise detection system can filter out detected signals that correspond to local vibrations rather than seismic events.

Claims

1. A method of detecting a seismic event, comprising:

detecting a primary wave of a seismic event using at least one sensor at a measurement location;

using at least one parameter of the detected primary wave to determine an estimated peak ground intensity at the measurement location without determining the magnitude of the seismic event;

determining an epicenter of the seismic event;

determining a distance of the measurement location from the epicenter; and

estimating the intensity of the seismic event at a specified location that is different from the measurement location using the determined estimated peak ground intensity at the measurement location, the determined distance of the measurement location from the epicenter, and a distance of the specified location from the epicenter.

2. The method of claim 1, further comprising issuing a warning if the intensity of the seismic event is above a threshold value.

3. The method of claim 2, wherein issuing the warning comprises issuing the warning as a probability function.

4. The method of claim 3, wherein the probability function is encoded using one parameter representing expected value and one parameter representing the deviation of the distribution.

5. The method of claim 1, wherein determining the epicenter comprises using information gathered from a first sensor and information gathered from a second sensor at another measurement location, the first sensor and the second sensor at another measurement location connected by a communication network.

6. The method of claim 1, wherein using at least one parameter of the detected primary wave to determine an estimated peak ground intensity at the measurement location comprises using an established empirical relation between the at least one parameter and the peak ground motion to determine the peak ground motion.

7. The method of claim 6, wherein the established empirical relation is based upon previous earthquake data.

8. The method of claim 1, wherein the at least one parameter comprises amplitude information in the time domain or the spectral domain.

9. The method of claim 1, wherein the at least one sensor comprises an accelerometer, a GPS sensor, a displacement sensor, or a velocity sensor.

10. The method of claim 1, wherein estimating the intensity of the seismic event at a specified location comprises using an established empirical relation between the peak ground intensity and the distance of the specified location from the epicenter.

11. The method of claim 10, wherein the established empirical relation is based upon previous earthquake data.

12. The method of claim 10, wherein the empirical relation comprises:

13. The method of claim 10, wherein the empirical relation can be represented as a curve of the decay of peak ground motion over distance from the epicenter.

14. The method of claim 1, wherein detecting a primary wave of a seismic event using at least one sensor comprises using a first sensor to obtain a first signal and a second sensor to obtain a second signal, correlating the first and second signals, and determining that the first and second signals correspond to a primary wave of a seismic event only if the correlation meets a set threshold value.

15. The method of claim 14, wherein correlating the first and second signals comprises comparing vector magnitude, direction vectors, or time-of-arrival.

16. A system for detecting a seismic event, comprising:

at least two sensors at a measurement location, the at least two sensors configured to detect a primary wave of a seismic event;

a controller, the controller configured to;

use at least one parameter of the detected primary wave to determine an estimated peak ground intensity without determining the magnitude of the seismic event;

determine an epicenter of the seismic event;

determining a distance of the measurement location from the epicenter; and

estimating the intensity of the seismic event at a specified location that is different from the measurement location using the determined estimated peak ground intensity at the measurement location, the determined distance of the measurement location from the epicenter, and a distance of the specified location from the epicenter.

17. The system of claim 16, wherein the controller is further configured to issue a warning if the intensity of the seismic event is above a threshold value.

18. The system of claim 17, wherein the controller is configured to issue the warning as a probability function.

19. The system of claim 18, wherein the probability function is encoded using one parameter representing expected value and one parameter representing the deviation of the distribution.

20. The system of claim 16, wherein the at least two sensors are at separate measurement locations, the measurement locations connected by a communication network.

21. The system of claim 16, wherein the controller is configured to use at least one parameter of the detected primary wave to determine an estimated peak ground intensity at the measurement location by using an established empirical relation between the at least one parameter and the peak ground motion to determine the peak ground motion.

22. The system of claim 21, wherein the established empirical relation is based upon previous earthquake data.

23. The system of claim 16, wherein the at least one parameter comprises amplitude information in the time domain or the spectral domain.

24. The system of claim 16, wherein at least one of the at least two sensors is an accelerometer, a GPS sensor, a displacement sensor, or a velocity sensor.

25. The system of claim 16, wherein the controller is configured to estimate the intensity of the seismic event at a specified location by using an established empirical relation between the peak ground intensity and the distance of the specified location from the epicenter.

26. The system of claim 25, wherein the established empirical relation is based upon previous earthquake data.

27. The system of claim 25, wherein the empirical relation comprises:

28. The system of claim 25, wherein the empirical relation can be plotted as a curve of the decay of peak ground motion over distance from the epicenter.

29. The system of claim 16, wherein a first sensor is configured to obtain a first signal and a second sensor is configured to obtain a second signal, and wherein a controller is configured to correlate the first and second signals and determine that the first and second signals correspond to a primary wave of a seismic event only if the correlation meets a set threshold value.

30. The system of claim 29, wherein the controller is configured to correlate the first and second signals by comparing vector magnitude, direction vectors, or time-of-arrival.

31. A method of detecting a seismic event, comprising:

detecting a primary wave of a seismic event using at least two sensors at a measurement location, wherein the at least two sensors are less than 500 m apart;

using at least one parameter of the detected primary wave to determine an estimated peak ground intensity at the measurement location;

determining an epicenter of the seismic event using only the at least two sensors at the measurement location; and

estimating the intensity of the seismic event at a specified location that is different from the measurement location using the determined estimated peak ground intensity at the measurement location, the determined distance of the measurement location from the epicenter, and a distance of the specified location from the epicenter.

32. The method of claim 31, wherein the at least two sensors are less than 200 m apart.

33. The method of claim 32, wherein the at least two sensors are less than 100 m apart.

34. The method of claim 31, further comprising issuing a warning if the intensity of the seismic event is above a threshold value.

35. The method of claim 34, wherein issuing the warning comprises issuing the warning as a probability function.

36. The method of claim 35, wherein the probability function is encoded using one parameter representing expected value and one parameter representing the deviation of the distribution.

37. The method of claim 31, wherein the at least two sensors are connected by a hard line communication network.

38. The method of claim 31, wherein at least one of the at least two sensors comprises an accelerometer, a GPS sensor, a displacement sensor, or a velocity sensor.

39. The method of claim 31, wherein detecting a primary wave of a seismic event using at least two sensors comprises using a first sensor to obtain a first signal and a second sensor to obtain a second signal, correlating the first and second signals, and determining that the first and second signals correspond to a primary wave of a seismic event only if the correlation meets a set threshold value.

40. The method of claim 39, wherein correlating the first and second signals comprises comparing magnitude, direction vectors, or time-of-arrival.

41. The method of claim 31, wherein the at least two sensors are identical.

42. The method of claim 31, wherein determining the epicenter comprises determining the epicenter as a probability density function in latitude and longitude.

43. The method of claim 42, wherein the probability density function is encoded using one parameter representing expected value in latitude in longitude, deviation along two primary axes, and an angle of rotation.

44. The method of claim 42, wherein the probability density function is determined using azimuth and dip information.

45. The method of claim 42, further comprising adjusting the probability density function using prior information about local geology, geometry of other measurement locations in the region, and the real-time status of other measurement locations.

46. A system for detecting a seismic event, comprising:

at least two sensors configured to detect a primary wave of a seismic event, wherein the at least two sensors are less than 500 m apart;

a controller, the controller configured to;

use at least one parameter of the detected primary wave to determine an estimated peak ground intensity;

determine an epicenter of the seismic event using only the at least two sensors at the measurement location; and

estimating the intensity of the seismic event at a specified location that is different from the measurement location using the determined estimated peak ground intensity at the measurement location, the determined distance of the measurement location from the epicenter, and a distance of the specified location from the epicenter.

47. The system of claim 46, wherein the at least two sensors are less than 200 m apart.

48. The system of claim 47, wherein the at least two sensors are less than 100 m apart.

49. The system of claim 46, wherein the controller is further configured to issue a warning if the intensity of the seismic event is above a threshold value.

50. The system of claim 49, wherein the controller is configured to issue the warning as a probability function.

51. The system of claim 50, wherein the probability function is encoded using one parameter representing expected value and one parameter representing the deviation of the distribution.

52. The system of claim 46, wherein the at least two sensors are connected by a hard line communication network.

53. The system of claim 46, wherein at least one of the at least two sensors comprises an accelerometer, a GPS sensor, a displacement sensor, or a velocity sensor.

54. The system of claim 46, wherein a first sensor is configured to obtain a first signal and a second sensor is configured to obtain a second signal, and wherein a controller is configured to correlate the first and second signals and determine that the first and second signals correspond to a primary wave of a seismic event only if the correlation meets a set threshold value.

55. The system of claim 54, wherein correlating the first and second signals comprises comparing magnitude, direction vectors, or time-of-arrival.

56. The system of claim 46, wherein the at least two sensors are identical.

57. The system of claim 46, wherein the controller is configured to determine the epicenter by determining the epicenter as a probability density function in latitude and longitude.

58. The system of claim 57, wherein the probability density function is encoded using one parameter representing expected value in latitude in longitude, deviation along two primary axes, and an angle of rotation.

59. The system of claim 57, wherein the probability density function is determined using azimuth and dip information.

60. The system of claim 57, wherein the controller is further configured to adjust the probability density function using prior information about local geology, geometry of other measurement locations in the region, and the real-time status of other measurement locations.

61. A method of detecting a primary wave of a seismic event comprising:

obtaining a first ground vibration signal from a first sensor at a first location;

obtaining a second ground vibration signal from a second sensor at a second location, the second location within 500 m of the first location;

correlating the first and second signals; and

only if the correlation of the first and second signals meets a set threshold, using at least one parameter of the first signal or the second signal to estimate the intensity of a seismic event.

62. The method of claim 61, wherein at least one of the first sensor or the second sensor is an accelerometer, velocity sensor, or displacement sensor.

63. The method of claim 61, wherein correlating the first and second signals comprises computing the difference in direction vectors of the first and second signals, and wherein meeting the set threshold comprises being less than a set difference.

64. The method of claim 61, wherein correlating the first and second signals comprises computing a cross-correlation peak of the first and second signals, and wherein meeting the set threshold comprises being below a set value.

65. The method of claim 61, wherein correlating the first and second signals comprises computing a time delay between the first and second signals, and wherein meeting the set threshold comprises being less than a set difference.

66. The method of claim 61, wherein correlating the first and second signals comprises computing a difference in magnitude of the first and second signals, and wherein meeting the set threshold comprises being less than a set difference.

67. The method of claim 61, further comprising obtaining first and second signals at a sampling rate over 100 Hz.

68. The method of claim 67, wherein the sampling rate is over 200 HZ.

69. The method of claim 68, wherein the sampling rate is at least 800 HZ.

70. The method of claim 61, further comprising issuing a warning if the intensity of the seismic event is above a threshold value.

71. The method of claim 70, wherein issuing the warning comprises issuing the warning as a probability function.

72. The method of claim 71, wherein the probability function is encoded using one parameter representing expected value and one parameter representing the deviation of the distribution.

73. The method of claim 61, wherein the obtaining and correlating steps are repeated continuously in real time.

74. The method of claim 61, wherein the at least two sensors are less than 200 m apart.

75. The method of claim 61, wherein the at least two sensors are less than 100 m apart.

76. A system for detecting a seismic event, comprising:

a first sensor at a first location, the first sensor configured to obtain a first ground vibration signal;

a second sensor at a second location, the second location within 500 m of the first location and configured to obtain a second ground vibration signal; and

a controller, the controller configured to;

correlate the first and second signals; and

only if the correlation of the first and second signals meets a set threshold, use at least one parameter of the first signal or the second signal to estimate the intensity of a seismic event.

77. The system of claim 76, wherein at least one of the first or second sensors is an accelerometer, velocity sensor, or displacement sensor.

78. The system of claim 76, wherein the controller is configured to correlate the first and second signals by computing the difference in direction vectors of the first and second signals, and wherein meeting the set threshold comprises being less than a set difference.

79. The system of claim 76, wherein the controller is configured to correlate the first and second signals by computing a cross-correlation peak of the first and second signals, and wherein meeting the set threshold comprises being below a set value.

80. The system of claim 76, wherein the controller is configured to correlate the first and second signals by computing a time delay between the first and second signals, and wherein meeting the set threshold comprises being less than a set difference.

81. The system of claim 76, wherein the controller is configured to correlate the first and second signals by computing a difference in magnitude of the first and second signals, and wherein meeting the set threshold comprises being less than a set difference.

82. The system of claim 76, wherein the first and second sensors are configured to obtain the first and second signals at a sampling rate over 100 Hz.

83. The system of claim 82, wherein the sampling rate is over 200 HZ.

84. The system of claim 83, wherein the sampling rate is at least 800 HZ.

85. The system of claim 76, wherein the controller is further configured to issue a warning if the intensity of the seismic event is above a threshold value.

86. The system of claim 85, wherein the controller is configured to issue the warning as a probability function.

87. The system of claim 86, wherein the probability function is encoded using one parameter representing expected value and one parameter representing the deviation of the distribution.

88. The system of claim 76, wherein the sensors are configured to repeat the obtaining steps in real time and the controller is configured to repeat the correlating step in real time.

89. The system of claim 76, wherein the at least two sensors are less than 200 m apart.

90. The system of claim 89, wherein the at least two sensors are less than 100 m apart.