Magnitude 3.4 Earthquakeof Fairfield, Illinois 2015-05-30

2015-05-30 00:41:14 (UTC) : North of Fairfield, Illinois

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Magnitude : 3.4

Event Time: Time and Date Starting of Earthquake Rupture 

• 2015-05-30 00:41:14 (UTC)

Earthquake data:

Location : Position of Epicenter 

38.458°N 88.355°W

Depth : Depth of starting Rupture 

17.7 km

Region : Fairfield, Illinois

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

a) 8km (5mi) N of Fairfield, Illinois

b) 50km (31mi) ENE of Mount Vernon, Illinois

c) 68km (42mi) E of Centralia, Illinois

d) 75km (47mi) SSE of Effingham, Illinois

e) 186km (116mi) SE of Springfield, Illinois

Location Uncertainty: 

Parameter	Value	Uncertainty
Magnitude	3.4 mlg	--
Location	38.458°N 88.355°W	± 0.6 km
Depth	17.7 km	± 0.9
Number of Phase Applied1	27
Minimum Distance2	9.08 km (0.08°)
Travel Time Residual3	0.4 sec
Azimuthal Gap4	52°

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)