... with the position of the instrumentally determined epicenter, although a node of enhanced shaking inferred within the main intensity V area implies an epicenter some 5–10 km north or northwest. The correlations of some local perturbations in both the 1993 and 1975 isoseisms with features in the Precambrian bedrock...

... isoseism can be determined. It was found that empirical equations relating m b to these areas, which were derived for central and northeastern United States earthquakes, also apply for events in the southeast. These empirical methods are used to estimate m b values for a set of historical Virginia...

.... Intensity values for the 1857 earthquake were obtained from the paper of Agnew and Sieh (1978). From the isoseismal map (Figure 2 of their paper) the intensity VII isoseism can be approximated by an ellipse with a semi-minor axis of 70 km and a semi-major axis of 330 km. Agnew and Sieh (1978) did not plot...

... in Figure 1. The distance at which each radius intersects each isoseism is measured, and later transferred to a computer card for statistical analysis. The usual situation is shown along radius 1. Other radii are marked to show the convention used in ambiguous situations: where a single radius crosses...

... and Lacroix, 1979) and the area within the intensity IV isoseisms (Nuttli et al., 1979). Based on the felt area and the area within the intensity IV isoseism, the magnitude of the 28 October 1923 earthquake is estimated to be 3.9 m (b) (Street, 1984). For the purposes of these comments, it is not important...

... of insufficient data. However, it is possible to estimate in the northwesterly and easterly directions, the distance from the epicenter to the MM intensity IV isoseism segments shown as solid lines in the figure. Using the average of these two distances, approximately 330 km, the common logarithm...

..., and the Transvaal. From the observers' descriptions the intensity of the shock (on the Rossi-Forel scale) was estimated, and from these data Map I, showing the isoseisms of this earthquake, was constructed. This gave the location of the epicenter of the shock as 24 ° 45' east longitude, 3o° 3o' south latitude...

... OF CHINESE EARTHQUAKES 961 data from the Longyao earthquake of 8 March 1966, for which there was a very thorough field investigation of the macroseismic area. Figure 1 presents isoseismal maps for the 8 March 1966 earthquake. The isoseisms were approximated by ellipses, and the semi-major and semi-minor axes...

... in the Australian Earthquake Catalog. Earthquake magnitude is related to the maximum-reported intensity, radius of perceptibility, and the radius of the MMIv isoseism. Rather surprisingly, we found that the equations are con- sistent with Richter's (1958) results for California, but give a difference of about one...

... Madrid, correspondence to conditions at Cincinnati, and absence of any confirmatory report, the best conclusion is that the Modified Mercalli intensity VII isoseism for the New Madrid sequence should include Chil- licothe, Ohio, but that a separate earthquake of that intensity should not be introduced...

... isoseisms, on the basis of the intensity values and on the similarity of intensity distribution to that of the earthquake of October 8, 1857, the epi- center is placed at approximately 39°N, 89½°W. This is east of the epicenter given in Earthquake History of the United States (Coffman and yon Hake, 1973...

..., in 1873, suggested the use of isoseiste, and this has received some support from English and Italian seismologists. Other Italian writers have employed isosisma, Baratta, 1895, which, in its English form of isoseism, has been sanctioned by Knott. As the word, or NOTES ON SOME SEISMOLOGICAL TERMS 35...

... and was less violent in the intervening blocks. A STUDY OF THE EARTttC~UAKE 267 Attention may here be called to the map, Plate 29, upon which a dotted line represents roughly the isoseism of intensity VIII R-F. This line encloses all the areas within which that intensity has been observed and is surrounded...

... techniques relied on a single intensity assignment; it did not provide accurate estimates of location or magnitude, and it provided no estimates of their uncertainty. A second generation of analysis techniques used isoseisms of the geographic distribution of all of the intensity assignments. Source location...

... difference code. They also computed the displacement and maximum velocity pattern. These simulations compare well with actual data from the Chinese network, with ground deformation derived from Differential Interferometric Synthetic Aperture Radar ( DInSAR ) measurements, and with modified Mercalli isoseisms...

... for the four earthquakes. In all cases Rossi-Forel (RF) intensities were con- verted to MM intensities according to the relations given by Wood and Neumann (1931). Intensity information for the 1906 San Francisco earthquake was taken from Lawson (1908). Because of the elongated character of the isoseisms...