caa a22 4500 477047521 CHVBK 20180405111334.0 cr unu---uuuuu 170330e19960201xx s 000 0 eng 10.1007/BF00876668 doi (NATIONALLICENCE)springer-10.1007/BF00876668 A determination of source properties of large intraplate earthquakes in Alaska [Elektronische Daten] [Hilary Fletcher, Douglas Christensen] Historically, large and potentially hazardous earthquakes have occurred within the interior of Alaska. However, most have not been adequately studied using modern methods of waveform modeling. The 22 July 1937, 16 October 1947, and 7 April 1958 earthquakes are three of the largest events known to have occurred within central Alaska (M s =7.3,M s =7.2 andM s =7.3, respectively). We analyzed teleseismic body waves to gain information about the focal parameters of these events. In order to deconvolve the source time functions from teleseismic records, we first attempted to improve upon the published focal mechanisms for each event. Synthetic seismograms were computed for different source parameters, using the reflectivity method. A search was completed which compared the hand-digitized data with a suite of synthetic traces covering the complete parameter space of strike, dip, and slip direction. In this way, the focal mechanism showing the maximum correlation between the observed and calculated traces was found. Source time functions, i.e., the moment release as a function of time, were then deconvolved from teleseismic records for the three historical earthquakes, using the focal mechanisms which best fit the data. From these deconvolutions, we also recovered the depth of the events and their seismic moments. The earthquakes were all found to have a shallow foci, with depths of less than 10 km. The 1937 earthquake occurred within a northeast-southwest band of seismicity termed the Salcha seismic zone (SSZ). We confirm the previously published focal mechanism, indicating strike-slip faulting, with one focal plane parallel to the SSZ which was interpreted as the fault plane. Assuming a unilateral fault model and a reasonable rupture velocity of between 2 and 3 km/s, the 21 second rupture duration for this event indicates that all of the 65 km long SSZ may have ruptured during this event. The 1947 event, located to the south of the northwest-southeast trending Fairbanks seismic zone, was found to have a duration of about 11 seconds, thus indicating a rupture length of up to 30 km. The rupture duration of the 1958 earthquake, which occurred near the town of Huslia, approximately 400 km ENE of Fairbanks, was found to be about 9 seconds. This gives a rupture length consistent with the observed damage, an area of 16 km by 64 km. Birkhäuser Verlag, 1996 Intraplate seismicity nationallicence historical earthquakes nationallicence deconvolution nationallicence source-time function nationallicence Fletcher Hilary Geophysical Institute, University of Alaska Fairbanks, 99775-7320, Fairbanks, AK, USA aut Christensen Douglas Geophysical Institute, University of Alaska Fairbanks, 99775-7320, Fairbanks, AK, USA aut pure and applied geophysics Birkhäuser-Verlag 146/1(1996-02-01), 21-41 0033-4553 146:1<21 1996 146 24 https://doi.org/10.1007/BF00876668 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00876668 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Fletcher Hilary Geophysical Institute, University of Alaska Fairbanks, 99775-7320, Fairbanks, AK, USA aut NATIONALLICENCE 700 1- Christensen Douglas Geophysical Institute, University of Alaska Fairbanks, 99775-7320, Fairbanks, AK, USA aut NATIONALLICENCE 773 0- pure and applied geophysics Birkhäuser-Verlag 146/1(1996-02-01), 21-41 0033-4553 146:1<21 1996 146 24 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer