scholarly journals SOME EFFECTS OF GEOLOGIC STRUCTURE ON RADIO RECEPTION

Geophysics ◽  
1943 ◽  
Vol 8 (2) ◽  
pp. 165-176 ◽  
Author(s):  
B. F. Howell,
Keyword(s):  
New Jersey ◽  
Fault Zone ◽  
San Andreas Fault ◽  
Geologic Structure ◽  
Fault Surface ◽  
San Jacinto Fault ◽  
San Andreas ◽  
San Bernardino

Radio fields at standard broadcast frequencies were examined over faults to determine how the geologic conditions affected the fields. The fields in rugged and densely inhabited areas were found to be too irregular to yield understandable patterns. Very small variations in the directions of the fields were suggested but not proven over the San Jacinto fault. No variations in intensity were found over the San Andreas fault, but variations were observed at some places over the Piedmont fault in New Jersey. Such variations might be due to higher conductivity of the fault zone, or to the addition of waves reflected and refracted at the fault surface. Weak areas near San Bernardino were noted, but could not be correlated with faults. It seems improbable that surveys using standard broadcast signals will be of much value in studying radio weak spots, although other approaches may be more revealing.

scholarly journals Latest Quaternary slip rates of the San Bernardino strand of the San Andreas fault, southern California, from Cajon Creek to Badger Canyon

Geosphere ◽  
2021 ◽  
Author(s):  
Sally F. McGill ◽  
Lewis A. Owen ◽  
Ray J. Weldon ◽  
Katherine J. Kendrick ◽  
Reed J. Burgette
Keyword(s):  
Confidence Interval ◽  
San Andreas Fault ◽  
Slip Rate ◽  
Alluvial Fan ◽  
Slip Rates ◽  
San Jacinto Fault ◽  
The Past ◽  
San Andreas ◽  
San Jacinto Fault Zone ◽  
San Bernardino

Four new latest Pleistocene slip rates from two sites along the northwestern half of the San Bernardino strand of the San Andreas fault suggest the slip rate decreases southeastward as slip transfers from the Mojave section of the San Andreas fault onto the northern San Jacinto fault zone. At Badger Canyon, offsets coupled with radiocarbon and optically stimulated luminescence (OSL) ages provide three independent slip rates (with 95% confidence intervals): (1) the apex of the oldest dated alluvial fan (ca. 30–28 ka) is right-laterally offset ~300–400 m yielding a slip rate of 13.5 +2.2/−2.5 mm/yr; (2) a terrace riser incised into the northwestern side of this alluvial fan is offset ~280–290 m and was abandoned ca. 23 ka, yielding a slip rate of 11.9 +0.9/−1.2 mm/yr; and (3) a younger alluvial fan (13–15 ka) has been offset 120–200 m from the same source canyon, yielding a slip rate of 11.8 +4.2/−3.5 mm/yr. These rates are all consistent and result in a preferred, time-averaged rate for the past ~28 k.y. of 12.8 +5.3/−4.7 mm/yr (95% confidence interval), with an 84% confidence interval of 10–16 mm/yr. At Matthews Ranch, in Pitman Canyon, ~13 km northwest of Badger Canyon, a landslide offset ~650 m with a 10Be age of ca. 47 ka yields a slip rate of 14.5 +9.9/−6.2 mm/yr (95% confidence interval). All of these slip rates for the San Bernardino strand are significantly slower than a previously published rate of 24.5 ± 3.5 mm/yr at the southern end of the Mojave section of the San Andreas fault (Weldon and Sieh, 1985), suggesting that ~12 mm/yr of slip transfers from the Mojave section of the San Andreas fault to the northern San Jacinto fault zone (and other faults) between Lone Pine Canyon and Badger Canyon, with most (if not all) of this slip transfer happening near Cajon Creek. This has been a consistent behavior of the fault for at least the past ~47 k.y.

Water-level fluctuations and earthquakes on the San Andreas fault zone

Geology ◽  
1975 ◽  
Vol 3 (8) ◽  
pp. 437 ◽  
Author(s):  
Robert L. Kovach ◽  
Amos Nur ◽  
Robert L. Wesson ◽  
Russell Robinson
Keyword(s):  
Water Level ◽  
Fault Zone ◽  
San Andreas Fault ◽  
Water Level Fluctuations ◽  
San Andreas
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