Magnitude 4.6 Earthquake of Iwaki, Japan 2015-04-24

2015-04-24 07:37:52 (UTC) :East-SouthEast of Iwaki, Japan

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Magnitude : 4.6

Event Time: Time and Date Starting of Earthquake Rupture 

• 2015-04-24 07:37:52 (UTC)

Earthquake data:

Location : Position of Epicenter 

36.459°N 142.852°E

Depth : Depth of starting Rupture 

34.9 km

Region : Iwaki, Japan

Directions and Distances :Directions and Distances from Geographical Reference in Close Proximity Which can be effected by Location Uncertainty

a) 187km (116mi) ESE of Iwaki, Japan

b) 191km (119mi) E of Kitaibaraki, Japan

c) 193km (120mi) E of Takahagi, Japan

d) 197km (122mi) E of Hitachi, Japan

e) 297km (185mi) ENE of Tokyo, Japan

Location Uncertainty: 

Parameter	Value	Uncertainty
Magnitude	4.6 mb	± 0.1
Location	36.459°N 142.852°E	± 8.0 km
Depth	34.9 km	± 7.7
Number of Phase Applied1	54
Minimum Distance2	240.56 km (2.16°)
Travel Time Residual3	0.79 sec
Azimuthal Gap4	136°

¹Number of phase Applied: 

In determining location of hypocenter, applied number of observations on P waves and S waves. The greater the more accurate prediction of EQ.

²Minimum Distance:

 Horizontal distance of nearest Station measured in Km from epicenter. The smaller the more accuracy in prediction of depth of EQ.

³Travel Time Residual:

 A way of measurement of fit of arrival time observed to arrival time predicted for particular location. The smaller the better fit of data.

⁴Azimuthal Gap: 

Expressed in degree; the smaller the smaller the error in horizontal positioning of EQ. Large uncertainty is considered when exceeds 180° (both depth and location)