Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Pure and applied geophysics 136 (1991), S. 143-154 
    ISSN: 1420-9136
    Keywords: Earthquake statistics ; earthquake hazard ; Vrancea seismogenic region
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract A maximum likelihood method is used to estimate the earthquake hazard parameters maximum magnitudeM max, annual activity rate λ, and theb value of the Gutenberg-Richter equation in the Vrancea (Romania) region. The applied procedure permits the use of mixed catalogs with incomplete historical as well as complete instrumental parts, the consideration of variable detection thresholds, and the incorporation of earthquake magnitude uncertainty. Our imput data, comprises 105 historical earthquakes which occurred between 984 and 1934, and a complete data file containing 1067 earthquakes which occurred during the period 1935–30 August, 1986. The complete part was divided into four subcatalogs according to different thresholds of completeness. Only subcrustal events were considered, and dependent events were removed. The obtained $$\hat b$$ value (=0.65) is at the lower range of the previously reported results, but it appears concurrent with conceptual and observational facts. The same concerns inferred value of $$\hat M$$ max = 7.8 and activity rate $$\hat \lambda $$ 4.0 = 5.34.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Pure and applied geophysics 140 (1993), S. 1-14 
    ISSN: 1420-9136
    Keywords: Crustal phases ; earthquake locations ; re-identification ; first arrival ; upper mantle ; granitic layer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract For crustal earthquakes of moderate or large size, the first reported phases at distant stations are usually the first predicted by the crustal model used. For smaller events, however, or for stations at larger distances, the first phase detected is often a later crustal phase of larger amplitude. This may be eitherPg which travels entirely in the upper crustal layer with a velocity of about 5.6 km/s, orP * with a path mainly in the lower crustal layer at a velocity of about 6.7 km/s. Many earthquake location programs do not take account of these phases, and treat their arrivals as if they were the earlier phasePn. At the International Seismological Centre we re-identify up to 200 crustal phases each month. This often results in significant improvement in position, the direct determination of depth or even the obtaining of a formal solution where none was possible before. We find that these re-identifications are needed in most continental areas of the world, and that the original crustal model of Jeffreys and Bullen still remains a useful standard.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...