System and Data Research Co., Ltd.

Yutaka NAKAMURA, Dr. Eng.
System and Data Research, Co., Ltd.

Observational Results of UrEDAS atPasadena and Other Locations

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within a few seconds initial P-wave detection
at single station independently

Estimation of Magnitude and Location
Vulnerability Assessment
Warning

UrEDAS Functions

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Vulnerability Assessment and Warning
based on M-D Relation

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Estimations will be done by twice;P-wave and S-wave arrivals

３．
Epicentral Distance
３．Epicentral
Distance // Depth
Depth

２．
Magnitude
２．Magnitude

１．
Epicentral Azimuth
１．Epicentral
AzimuthEstimation of Magnitude and Location

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P-wave Recognition and Azimuth Estimation
using a Single Station Information

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Continuous Processing Concept for Earthquake Detection

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Relation between Azimuth by UrEDAS and Authorities

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Relation between Magnitude and Period ofInitial Motion

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Evaluation of Initial Motion Frequency

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Real-time Estimation of Predominant Frequency of Vibration

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Relationship between
Initial Period and JMA Magnitude

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Examples of Magnitude Comparison
between UrEDAS Initial and JMA Final

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In general, the magnitude is calculated from the amplitude of the initialmotion and the epicentral distance. According to this, the epicentral
distance can be estimated using the amplitude of an initial motion andestimated the magnitude by initial period. The depth can be estimatedstatistically using a parameter the ratio of vertical to horizontal initialmotion as a kind of seismic wave incident angle.

Estimation of Epicentral Distanceand Depth

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ExamplesExamples ofof Earthquake
Earthquake Monitoring
Monitoring byby UrEDAS
UrEDAS

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Berkeley UrEDAS locates just above
the Hayward fault while Pasadena
UrEDAS is surrounded by fault. Either
station is under not so good condition. In
spite of the influence of faults, Pasadena
UrEDAS shows better estimate accuracyof focal parameters than Berkeley
UrEDAS, and performance of earthquake
detection is effectively at both station.

Pasadena and Berkeley UrEDAS observation started
in July 2000, and in February 2001, respectively.
These observations are supported by Caltech and UC
Berkeley, respectively. After earthquake detection,these UrEDAS will send e-mail to whom concern inreal time. Former type of Pasadena UrEDAS was atwork from September 1993 to August 1999, andobserved the 1994 Northridge Earthquake.

UrEDAS Observations in California

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PAS station

Pasadena UrEDAS

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M2: up to 80km
M4: up to 1000km>M7:expected to detect
everywhere on the earth

Detection Range

Reported Earthquakes via e-mailfrom Pasadena UrEDAS

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Comparison between Onsite Processing Results andFREQL Simulation Results for Pasadena UrEDASFREQL
Simulation
ResultswithOnesecondOn-site
Resultswith
Threeseconds

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BKS station

Berkeley UrEDAS

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>M6:expected to detect
everywhere on the earth

M2: up to 80km
M4: up to 1000km

Detection Range

Reported Earthquakes via e-mailfrom Berkeley UrEDAS

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Comparison between Onsite Processing Results andFREQL Simulation Results for Berkeley UrEDAS

FREQL
Simulation
ResultswithOnesecondOn-site
Results
withThreeseconds

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Recent Examples of On-Site Real-time Process

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FREQL and AcCo

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All in One Five inches Cube!!

Hyper UrEDAS

Systems for Future

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Thank you for your kindattention!

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