EARTHQUAKE CLOUDS AND
SHORT TERM PREDICTION

Earthquake Database Problems

- 5/15/2001 -

When reading the earthquake data "20001206 17:11:06 39.566N, 54.799E, 6.7Mb A (7Mw, 6.9Me, 7.5Ms) Turkmenistan", one may think its errors as small as "0.001" for the both latitude and longitude, and "0.1" for the magnitude according to the International Error Law. However, it is not true because earthquake data are special. In this essay, I will discuss how special earthquake data are, how their errors affect seismological study, and how we can overcome those error problems.

First, Table1 shows19 sets of data from different countries for the Turkmenistan earthquake. Their average, maximum and minimum of latitude, longitude, and magnitude are exhibited in Table 2, whose errors are not small.

One may think that different countries, of course, produce various data. Table 3 reveals a few normal data (not the largest) from the USGS and its two branches: Pasadena Office in Southern California and Berkeley Office in Northern California. The database does not show the differences between those latitude data, and longitude data, but the magnitude data. The USGS uses "MB", and the both branches use "ML". The table exposes a conflict that sometimes there is no big difference between "Mb" and "ML", but sometimes it can reach 1. Moreover, the data of the both branches are also different, and their magnitude difference can reach 1 ML sometimes (See Table 4).

Table 4 shows that the USGS knows the problem, so its experts change data to make a balance, which is respectable. Moreover, the < Earthquake Database System Documentation > of the USGS announces its instrumental data errors as 0.1, 0.2, 0.5, and 1 degree for Rank A, B, C, and D correspondingly (1 degree equals about 100 km), so one should not misread. In addition, what evidence supports the above error ranks needs more study.

Except error, data loss is another special problem of earthquake databases. The first lost data I found from the World Earthquake Database of the USGS was the 5.6 Turkey earthquake on June 1, 1997 [1]. More examples are in Box < Photos & Images >, whose data sources are mentioned. By contrast, the Chinese Earthquake Database lost more than the USGS, which was one main reason why I did not devote myself to earthquake prediction when I was in China.

Second, both data loss and data error affect earthquake prediction seriously, for example, the lost 5.6 Turkey data had bothered me for three years. Moreover, data errors make databases a rubber rule, by which, a correct prediction could be judged as wrong, too. Moreover, to avoid this problem, I have to extend the windows of my predictions or to increase their probabilities.

The both special problems also affect other seismological study, for example, a paper defined foreshock as "M>=2 occurring within 5 km horizontally and 30 days of the mainshock", according to which, it set up a relationship between mainshocks and their related foreshocks [2]. Since the data errors for the paper were far bigger than the definition, the conclusion of that paper may not be meaningful.

Finally, let's discuss how we can overcome those problems. In Essay < An Suggestion Due To Southern Alaska Geoeruption >, I already pointed out that "the measure does not have a uniform standard, like the 1 Kg Mass Standard in Paris or other international standards, to check the measure error", which is the cause of why those errors exist.

To solve the problem, I suggested, "We need a standard earthquake. Due to no nature earthquake is available, we should create an artificial earthquake, whose latitude, longitude, depth, and magnitude can be set up exactly by an underground chemical bomb." Relying on those artificial earthquakes, we will be able to check the errors of earthquake data exactly.

Except the above authoritative method, some rare geoeruptions and earthquake clouds can be employed to check location errors sometimes, for example, the geoeruption in Image 20001120 9:00 [3], exhibited in our homepage before the Turkmenistan earthquake on December 6, 2000, shows its epicenter at about 39.3 N, and 55.1 E. An example for earthquake clouds is in Image 20010103 5:00 [4]. I had pinpointed its epicenter with the arrow and its magnitude 4.3 ten days before the earthquake exactly. However, this method contains error or is not as authoritative as artificial earthquakes.

 

 

Table 1: Various data for the Turkmenistan earthquake on December 6, 2000

 

 

No.

Time

Latitude (N)

Longitude (E)

Magnitude

Rank

Producer

1

17:11:43.0

39.0

49.0

6.8 Mb

A

LED

2

17:11:27.1

39.7

51.0

6.2 M

A

MAD

3

17:11:23.6

40.4

52.3

7.0 Mb

A

LDG

4

17:11:19.0

40.4

53.7

6.5 Mm

A

LOR

5

17:11:18.2

40.4

54.0

6.5 M

M+

CSEM

6

17:11:16.0

40.0

53.0

6.4 Mm

A

LIC

7

17:11:13.0

39.4

54.0

6.0 Md

M

KAN

8

17:11:07.9

39.7

54.9

7.2 Mw

M

NEIM

9

17:11:07.9

39.7

54.9

7.4 Ms

M

NEIR

10

17:11:07.3

39.5

55.0

6.7 Mb

A

NEIA

11

17:11:06.0

39.5

55.1

6.5 Mm

A

TBGS

12

17:11:05.8

39.7

54.7

7.4 Ms

A

GSSA

13

17:11:05.8

39.7

54.7

7.4 Ms

M

GSSC

14

17:11:05.3

39.8

54.5

6.7 M

M+

CSEM

15

17:11:04.7

39.8

55.2

7.0 Ms

M

SED

16

17:11:04.7

39.8

55.2

5.8 Mb

M

SED

17

17:10:57.4

39.5

56.2

7.0 Mb

A

SED

18

17:10:57.4

39.5

56.2

6.4 Ms

A

SED

19

17:10:31.1

39.3

56.8

6.5 Mb

A

 

 

 

Table 2: The Average, The Maximum & The Minimum of Latitude, Longitude, & Magnitude

 

 

Item

Latitude (N)

Longitude (E)

Magnitude

Maximum

40.4

56.8

7.4

Minimum

35,3

49.0

5.8

Average

39.5

54,2

6.7

 

 

Table 3: The Data Difference Among The USGS & Its Two Branches

 

 

Date

Time

Latitude (N)

Longitude (W)

Mb(USGS)

ML(PAS)

ML(BRK)

1994 01 18

0:43:08

34.377

118.698

5.4

5.2

5.5

1994 01 18

15:23:46

34.379

118.561

4.8

4.8

5.0

1994 01 24

5:50:24

34.359

118.629

4.2

5.0

4.4

1994 01 28

20:09:53

34.374

118.495

3.8

4.2

4.3

1994 01 29

11:20:35

34.305

118.579

4.9

5.1

5.4

1994 01 29

12:16:56

34.278

118.611

3.3

4.3

4.4

1994 04 06

19:01:04

34.192

117.095

4.4

4.8

5.0

1994 04 21

16:37:15

36.3

120.427

4.1

4.5

4.5

 

 

Table 4: Good Work, Pasadena Station Reviewed Data

 

 

Date

Time

Latitude (N)

Longitude (W)

ML(PAS) before

ML(PAS) later

ML(BRK)

1990 02 28

23:43:36

34.14

117.7

5.2

5.5

6.2

1994 01 17

12:39:39

34.261

118.534

4.5

4.9

 

1992 08 17

20:41:52

34.195

116.862

5.3

5.1

 

1992 06 29

14:08:37

34.106

116.402

4.9

5.5

 

1992 06 29

14:13:38

34.108

116.404

5.4

5.0

 

 

 

References & Images

 

1.      "My Prediction No. 23 Is Correct" on August 2, 2000

2.      R.E. Abercromble & J. Mori defined. Occurrence patterns of foreshocks to large earthquakes in the western United States. Nature 381, 303~307 (1996)

3.      Fig. 1 Image 20001120 9:00 The 7.2 Turkmenistan Geoeruption

4.      Fig. 2 Image 20010103 5:00 The 4.3 Southern California Earthquake Cloud

 


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Updated: May15, 2001 | Webmaster