The Value of Improved ENSO Prediction to U.S. Agriculture

The economic value of long-range weather prediction is measured by the increase in social welfare arising from the use of the prediction in economic decisionmaking. This paper describes a study of the economic value of ENSO prediction to U.S. agriculture. The interdisciplinary study involved the analysis of data and models from meteorology, plant science, and economics under a framework based on Bayesian decision analysis. The estimated annual value of perfect ENSO prediction to U.S. agriculture is $323 million.     

A gamma spectrometric study of Mont-Blanc granite samples

Summary Gamma-ray spectra of the samples were measured by standard laboratory multichannel spectrometry. The weighted least squares method was applied to the digital output data in order to determine the concentrations of U²³⁸, Th²³² and K⁴⁰ present. U and Th increase towards the rim of the massif (from 4 ppm U and 20 ppm Th in the coarse-grained central facies to 23 ppm U and 42 ppm Th in the fine-grained rim variety), whereas K remains fairly constant at 3.85%.On leave Eidgenössische Technische Hochschule, Zurich (Switzerland)     

The Lake Lahontan highstand: age, surficial characteristics, soil development, and regional shoreline correlation

The Lake Lahontan basin has been the site of numerous pluvial lakes during the Pleistocene. We address the question of whether or not the highest remnant shoreline features around the perimeter of the lake were produced during the most recent Sehoo highstand (13 ka), the penultimate Eetza highstand (140–280 ka), or both. To do so, we document surficial characteristics, morphologic preservation, and soil development on multiple Sehoo beach barriers in the Jessup embayment to define the range in characteristics displayed by latest Pleistocene beach features. Sehoo barriers generally exhibit original constructional morphology that has been little modified by erosion. Soils developed on Sehoo barriers are generally thin and weakly developed and are strongly influenced by the introduction of eolian fines into the predominately clast-supported coarse beach gravels. Similar observations from 13 other highstand barriers and from seven older-than-latest Pleistocene paleosols located around the basin form the basis for a regional comparison. Based on similar characteristics, including the degree of morphologic preservation and weak soil development, we conclude that the widespread and nearly continuous high shoreline around the perimeter of Lake Lahontan dates from the most recent major lake cycle in all areas except in the Walker Lake subbasin. In the Walker Lake subbasin, isolated early to middle Pleistocene lacustrine outcrops and landforms are elevated as much as 70 m above the late Pleistocene limit, but are differentiated by their degraded form and lack of continuity around the subbasin. Similar unambiguous landforms were not observed elsewhere and at similar elevations in the northern subbasins of Lake Lahontan.     

Reappraisal of major African earthquakes,south of 20°N, 1900–1930

We have re-examined those earthquakes in Africa south of 20°N, in the period 1900–1930, that appear from instrumental or macroseismic evidence to have a magnitude of 5 3/4 or greater. We identify more than 50 such events, about twice as many as listed by Gutenberg and Richter (1954). We find that the combined use of early instrumental readings and macroseismic information gleaned from previously untapped sources gives the best control of location. Instrumental relocation is difficult because of the lack of stations in Africa and the very uneven global distribution. For the low-gain, medium-period instruments then in use, the best control often comes from using the maximum Airy phase of surface waves. Similarly, there is a lack of sources of macroseismic information, and the simple building practice makes it difficult to assess intensity. We have recalculated magnitude Ms uniformly using the Prague formula. We discuss these problems and show that it is likely that our list is complete only down to magnitude about 6, and that the seismic record for Africa before this century will probably remain incomplete for events of all magnitudes.Of the 54 events in our list 20 are between magnitude 6 and 7, and the largest is the Rukwa earthquake of 1910 in Tanzania (Ms 7.4). The only other African event known to rival it in size is that in southern Sudan on 20 May 1990 (Ms 7.2).     

Large-magnitude Central American earthquakes, 1898–1994

We have collected and re-examined macroseismic information for large Central American earthquakes since the beginning of the period of instrumental recording about one hundred years ago, and combined this with a reassessment of early instrumental information to produce a catalogue of 51 events that, we believe includes ail those with magnitudes ( Ms ) greater than 7.0. We have reassessed surface-wave magnitudes by consulting station bulletins and we have derived a correction that gives an equivalent Ms for events of intermediate depth. We have also developed a regional relationship between Ms and seismic moment, which enables us to estimate the seismic slip rate across the Middle American Trench. Our best estimates give an average slip rate several times smaller than suggested convergence rates, but with the seismic slip in the central segment of the trench almost an order of magnitude smaller than that in the segments on either side. The low seismic slip rate may indicate aseismic crustal deformation     

Tsunami risk analysis for China

Historical data have been used in this paper, in particular that available on the tsunami history and the geological and seismological characteristics along the coasts of China. The nature and effects of both local tsunamis and tele-tsunamis on the coasts of China are analyzed. The coastal response of China to tsunamis is estimated theoretically, also. Finally, the tsunami risk for the coast of China is calculated and the zonation of preliminary tsunami hazard of China is mapped for three levels of hazardicity.