Earthquake precursors in Japan: Precursor time and detectability

Rikitake, Tsuneji

doi:10.1016/0040-1951(87)90029-1

Cited by 106 publications

(79 citation statements)

References 3 publications

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“…On the basis of precursor data published up to 1977, Rikitake (1979) has given a relationship between precursor time (T) and earthquake magnitude (M) which was obtained on the basis of the best-fitting straight line using least square method as follows: log T = 0.6M − 1.01 . Rikitake (1987) modified the relation on the basis of 14 radon data sets and based on a general linear equation log T= a + bM, as: log T = (-0.47 ± 0.73) + (0.28 ± 0.12)M , which holds well for all the precursor disciplines. Using a log-linear relationship between precursor time and earthquake magnitude, Scholz et al (1973) established a relationship on the basis of a limited data set of radon anomalies as well as other precursors but this relationship was found to have a limited application (Hauksson, 1981).…”

Section: Empirical Algorithmsmentioning

confidence: 99%

Earthquake Prediction Studies Using Radon as a Precursor in N-W Himalayas, India: A Case Study

Walia¹,

Virk²,

Yang³

et al. 2005

Terr. Atmos. Ocean. Sci.

110

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30 -34°N, 74 -78°E). The influence of meteorological parameters viz. temperature, rainfall, relative humidity and wind velocity on radon concentration was qualitatively evaluated. The radon exhalation showed positive correlation with temperature, rainfall, relative humidity and negative correlation with wind velocity. Both positive and negative radon anomalies were recorded. The study reveals the precursory nature of radon anomalies and their correlation with microseismic events in 62% of the cases but prediction of earthquakes is yet a remote possibility. From the analysis it has been found that radon anomaly is not only influenced by seismic parameters but also by meteorological parameters and the nature of carrier gases/fluids. To learn more about the phenomenon, simultaneous recording of various gases (He, CO 2 , CH 4 ) and meteorologi- TAO, Vol. 16, No. 4, October 2005 776 cal parameters, together with multiple continuous measurements of radon have been suggested.

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Section: Empirical Algorithmsmentioning

confidence: 99%

Earthquake Prediction Studies Using Radon as a Precursor in N-W Himalayas, India: A Case Study

Walia¹,

Virk²,

Yang³

et al. 2005

Terr. Atmos. Ocean. Sci.

110

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“…It is known that the M-Dmax relation for geoscientific precursors can be approximately expressed by an equation similar to Eq. (1) (Rikitake, 1987). In obtaining Eq.…”

Section: Detectability As a Wholementioning

confidence: 99%

“…In order to see where a macro-anomaly precursor appears, the writer first of all examines the relation between earthquake magnitude (M) of the main shock and the epicentral distance (D) with respect to the data for the first six earthquakes in a fashion similar to the analysis for geoscientific precursors (Rikitake, 1987). Since the data are too numerous, the following approach is made to evaluate the overall tendency.…”

Section: Detectability As a Wholementioning

confidence: 99%

“…It is interesting to note that the epicentral distance for which we may expect appearance of a macro-anomaly precursor is a few times as large as that for the area where the seismic energy is stored and so most aftershocks occur. It has been shown by Rikitake (1987), however, that a geoscientific precursor sometimes appears at a much greater distance depending upon precursor disciplines. hard to think that animals can directly sense the crustal strain of the said order, it is surmised that they probably react to some changes in microshock, weak change in electric and magnetic fields, change in underground water level and so on that are possibly associated with a small crustal deformation.…”

Section: Detectability As a Wholementioning

confidence: 99%

“…These data are certainly useful for clarifying the nature of earthquake precursors of various geoscientific disciplines (Rikitake, 1987).…”

Section: Introductionmentioning

confidence: 99%

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Nature of Macro-Anomaly Precursory to an Earthquake.

Rikitake

1994

J,Phys,Earth

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Nature of macro-anomaly precursory to an earthquake such as anomalous animal behaviour, changes in underground water and hot springs and so on is studied based on an extensive data set related to a number of large earthquakes in Japan.It turns out that the larger the magnitude of the main shock, the wider the area over which macro-anomalies are observed. Underground water and hot spring anomalies appear in an area where a marked crustal deformation can be expected to take place. The area for anomalous animal behaviour is slightly wider than that.No dependence of precursor time of macro-anomaly on main shock magnitude is found for an individual earthquake. However, there is a certain regularity of precursor time distribution. The maximum frequency of precursor appearance occurs around one day before the main shock. The mean precursor time takes on a value amounting to 0.42 day.It is likely that animals of smaller size such as rat, squirrel and so on become tumultuous earlier than those of larger size such as dog, pig, cow, and so on.Much macro-anomaly precursor data is spurious. Changes in synthetic probability of the main shock occurrence with time when multiple signals appear are evaluated in two ways: one is assuming the reliability, r, which is defined by the ratio of genuine data to the total (genuine and spurious) data, for all the actual data. The other is obtained from a computer simulation of random appearance. Comparing the two evaluations, it seems appropriate to assume that r amounts to 0.05 or thereabouts.

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Are there new findings in the search for ULF magnetic precursors to earthquakes?

Masci

Thomas

2015

JGR Space Physics

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Moore (1964) in a letter published in Nature reported disturbances in geomagnetic field data prior to the 27 March 1964 Alaska earthquake. After the publication of this report, many papers have shown magnetic changes preceding earthquakes. However, a causal relationship between preearthquake magnetic changes and impending earthquakes has never been demonstrated. As a consequence, after 50 years, magnetic disturbances in the geomagnetic field are still candidate precursory phenomena. Some researchers consider the investigation of ultra low frequency (ULF: 0.001–10 Hz) magnetic data the correct approach for identifying precursory signatures of earthquakes. Other researchers, instead, have recently reviewed many published ULF magnetic changes that preceded earthquakes and have shown that these are not actual precursors. The recent studies by Currie and Waters (2014) and Han et al. (2014) aim to provide relevant new findings in the search for ULF magnetic precursory signals. However, in order to contribute to science, alleged precursors must be shown to be valid and reproducible by objective testing. Here we will briefly discuss the state of the art in the search for ULF magnetic precursors, paying special attention to the recent findings of Currie and Waters (2014) and Han et al. (2014). We do not see in these two reports significant evidence that may support the observation of precursory signatures of earthquakes in ULF magnetic records.

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Earthquake precursors in Japan: Precursor time and detectability

Cited by 106 publications

References 3 publications

Earthquake Prediction Studies Using Radon as a Precursor in N-W Himalayas, India: A Case Study

Earthquake Prediction Studies Using Radon as a Precursor in N-W Himalayas, India: A Case Study

Nature of Macro-Anomaly Precursory to an Earthquake.

Are there new findings in the search for ULF magnetic precursors to earthquakes?

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