ALBERT

Description: The permanent rotation of the N.E.Pacific Rift is divided into three first-order rotations covering the whole rift between 20° and 60° N. during the last 80 mio years. The general movement of a clockwise rotation (35-40° altogether) was interrupted during the time between 40 and 20 m.y.b.p. by a weak counterclockwise one (8° altogether). These superordinate rotations can be subdivided in smaller ones with an average duration of 10 m.y. only. It is to suppose that all these rotations are a readjustment of the rift to a changed position of the spreading pole. Compared to it, short-time, oscillatory rotations represent compensating movements of the rift and stabilizing efforts of the plate. For the S.E.Pacific Rift it is supposed that the. Counterclockwise rotation taking place there for the last 7 m.y. is continuing, as may be concluded from the distribution of earthquake epicentres. Furthermore, the problems of pendulum movements and hinge zones at the S.E. and N.E.Pacific Rifts are discussed, which represent the magmatic activity of the rift. Hinge zones are lines of weakness of rifts, which can become fault zones. Up to now they were not mentioned in literature. The internal deformations of the Pacific Plate and Juan de Fuca Plate off California indicated by kinks of the rift, fault-folding and strike slip faults became intense about 1-2 m.y.b.p.

Description: 1. Introduction 2. Superordinate rotations of the East Pacific Rift between 20° and 60° N. 2.1. The clockwise rotation of the N.E. Pacific Rift 80 m.y.b.p. (1st period) 2.2. The counterclockwise rotation of the N.E. Pacific Rift :from 71 to 63 m.y.b.p. (2nd period) 2.3. Rotations of the rift during a transitional stage about 65 to 60 m.y.b.p. (3rd period) 2.4. The great clockwise rotation of the N.E. Pacific Rift 63 to 50 m.y.b.p. (4th period) 2.5. Rotations with a stabilizing function in a transitional stage from 50 to 40 m.y.b.p. (5th period) 2.6. The great counterclockwise rotation of the N.E. Pacific Rift 43 to 20 m.y.b.p. (6th period) 3. Total rotation of the East Pacific Rift between Clarion and Aja Fracture Zones 3.1. Sum of rotations of the rift 3.2. Special position of the plate section between 33° and 37° N. 3.3. The significance of the Mendocino-Pioneer double structure 4. Rotations of the Pacific-Antarctic Rift between 30° and 65° s. 4.1. Complex movements of the rift 4.2. Recent tendencies 5. Magmatic activity of the rift 5.1. Characteristics of rift activity 5.2. Hinge zones of the rift rotations 6. Plate deformation 6.1. Rift rotation at a collision of plates 6.2. Rift shortening due to compression 7. Conclusions References

Description: The tables and graphs result from evaluation of Model 1 (see Veröffentlichungen des Zentralinstituts für Physik der Erde, Nr. 41, Potsdam 1976). They help to approximate values of the hydrostatic pressure P, the bulk modulus and its pressure derivative and the seismic parameter of a sample at any volume contraction x in the range between 0.5 and 1 if these quantities referred to the initial state (P = 0) are known. The considered functions are tabulated for a set of grid points of the rectangle 0.5 ≤ x ≤ 1, 2.1 ≤ ϰ_1 ≤ 10, where ϰ_1 is the initial value of the pressure derivative of the bulk modulus. The lattice pitchs are 0.01 in x and 0.1 in ϰ_1. The inverse problem can also be solved approximately with the aid of the tables and, above all, the plots presented here by using the "method of corresponding curves".

Description: Summary 1. Preface 2. Theoretical excursus 3. Some remarks on Model 1 4. Instructions for using tables and plots 5. References 6. Tables and figures

Description: This 3rd International Symposium "Geodesy and Physics of the Earth" was according to its tenor the continuation of the Symposia of 1970 and 1973 dealing with the same basic topic. It was especially devoted to the possibilities of Satellite Geodesy to study geodynamic processes. By this also those problems of the use of observations of artificial satellites for geodetic and geophysical purposes were dealt with that had regularly been treated in the preceding years and will be treated further by A. Massevitsch in the symposia presided by her. Several papers were devoted especially to the problems of the Special Study Group 5.49 of the International Association of Geodesy "Use of Geodetic Data for Studies of Earth-Moon-System" (President E. Tengström). Part 2 : Global and Planetary Dynamics of the Earth

Description: Evaluation of numerous data from different methods of measurement and theories applied in high-pressure physics shows that the strain energy of a monophase system, which represents the low- or a high-pressure phase of a hydrostatically compressed substance mostly relevant to planetary physics, approximates to a term proportional to the square of an auxiliary function of the volumetric contraction, the bulk modulus and its successive partial derivatives with respect to pressure at the initial state of the thermodynamical system. From this it follows that new-defined polynomial equations in the initial values of the bulk modulus and its pressure derivatives must be satisfied, which is checked for many elements, halides, oxides, minerals, and rocks. Using a suitably chosen auxiliary function, the strain energy, pressure, bulk modulus and its first pressure derivative at any equilibrium state of the monophase system are represented by approximation functions of the volumetric contraction as well as the initial values of the bulk modulus and its derivatives. The information content of these functional relations called Model N if they include derivatives of the bulk modulus only up to the order N surpasses, already in the cases N = 1 end N = 2, that of other relations hitherto used for interpreting the compressional behaviour of different substances. Model 1 is discussed on the base of more than 70 substances with various compressional properties, among them stishovite and solid hydrogene, proved to be suitable, in particular, for the physics of the interiors of the Earth and of terrestrial planets. Considering the reliability of the data material available, Model 1 is pointed out to predict experimental values from the tested substances for volumetric contractions down to about 0.5 with a relative error between 1 % and 5 %. Model 2, extending the information volume of Model 1, turns out to be appropriate for volumetric contractions less than 0.5 as is the case in the interiors of the Jovian planets. For practical use of both models tables and graphs of sensitivities and errors of significant quantities are presented. In case data from shock-wave experiments on rocks and minerals are available, Model 1 is used for identification of crystal structures of high-pressure phases. As a result, for the majority of high-pressure phases the compressional behaviour differs from that of the corresponding oxide mixtures. For some substances new conclusions on their crystal structures can be drawn.

Description: 1. Introduction 2. Basic relations 3. Approximations for the equation of state 4. The conditions of the auxiliary variable 5. Development of Model 1 and Model 2 6. Practical analysis of the models 6. 1. Preliminaries 6.2. The parameters "0 and "1 6.3. Intercomparison of different forms of the equation of state 6.4. The parameter n2 6.5. Problems of accuracy 6.6. Discussion of [x,P]-data of elements 6.7. Discussion of [x,P]-data of halides 6.8. Discussion of [x,P]-data of oxides, minerals, and rocks 6.9. On the "interpolating equations of state" 7. Conclusion 8. Tables and Figures References

Description: The present number contains the papers read at the conference "Statistical and Tectonophysical Aspects of Seismicity" held from May 16 to 18, 1972, at the Central Earth Physics Institute of the German Academy of Sciences of Berlin, Jena branch, which serve as a basis for the discussions of the working group “Statistical Methods" within the subcommission "Seismicity of Europa" of the European Seismological Commission. In his opening speech the Director of the institute, Prof. STILLER, pointed out the importance of quantitative representation of seismicity for the complex problems of the project of geodynamics. The chairman of the European Seismological Commission, Prof. SAVARENSKY, Moscow, emphasized the statistical aspects of seismicity and explained the potentialities of physical interpretation of the laws established as well as their application to estimating the earthquake risk under various aspects. SCHENKOVÁ analysed the chronological succession of the earthquake of the northeastern Mediterranean in the period (1901, 1967) in the light of several models, from which an optimum model was found by the x²-test. PURCARU examined models of the frequency-magnitude dependence, e.g. those of UTSU and of OKADA, from the view-point of information theory. In two papers read by PANZA the seismicity of Italy including the fundamentals of representation was discussed, where the GUTENBERG-RICHTER magnitude-frequency relation is the underlying principle. Its coefficients were determined for the various seismotectonic units of Italy. Moreover, models of intensity distribution about the epicentres were set up for these regions. On the basis of seismic data going back as far as to the Birth of Christ maps of the seismic risk and of the active faults were then drawn up. Furthermore, PANZA demonstrated the great dependence of the magnitude value as obtained from the seismic surface waves on the focus depth of an earthquake in the earth's crust. MAAZ and PURCARU as well as NEUNHÖFER and MAAZ were concerned with logarithmically normal distributions of the frequency of earthquakes over the magnitude or energy, the determination of their coefficients and their confidence intervals. PROCHÁZKOVÁ pointed out the necessity of standardized methods for determining the parameters of the GUTENBERG-RICHTER frequency-magnitude distribution and gave recommendations in this respect. Two papers by ULLMANN and MAAZ established the connection of the seismicity function as energy flow density with the energy distribution in the focus by means of the BÅTH-DUDA formula for focus volumes and rendered a generalization of the seismicity function in which the inaccuracy of the focus coordinates is statistically considered.

Description: Vom 25. bis 27. Mai 1970 fand in Potsdam eine Tagung der Arbeitsgruppe "Seismologie und Physik der extremen Bedingungen" der CSE statt. Die Sitzung stand unter dem Thema "Physikalische Parameter und seismische Geschwindigkeiten". Von den Teilnehmern wurden auf der Sitzung Vorträge zu folgenden Themen gehalten: HÖFER, K.-H.: Erkenntnisse der Gebirgsmechanik über.das mechanische Verhalten verschiedenartiger Gesteine HURTIG, E.; u. a.: Zur Bedeutung der Crack-porosity bei Messungen unter hydrostatischem Druck FUCHS, K.; LIEBAU, F.; MAYER-ROSA, D.: Lateral inhomogeneities of the Earth's mantle and their petrological interpretation MAYER-ROSA, D.; MÜLLER, St.: Velocity and density distributions in the upper mantle of Europe as derived from seismological observations SCHULT, A.: Die Druckabhängigkeit der CURIE-Temperatur von Titanomagnetiten SCHOBER, M.; SCHULT, A.: Die elektrische Leitfähigkeit von natürlichen Olivinen bei hohen Drücken und Temperaturen STILLER, H.: Betrachtungen zum Näherungscharakter von Festkörpermodellen für das Erdinnere TEISSEYRE, R.: Influence of pore-fluid pressure in rocks on tensile cracking under high pressure VOLLSTÄDT, H.: WAGNER, F.C.: Die Hochdrucktechnologie des Zentralinstituts Physik der Erde in Potsdam und die Zusammenarbeit mit dem Zentralinstitut Physik der Erde in Moskau auf dem Gebiet der Hochdruck-Hochtemperatur-Physik Außerdem wurden zum Thema der Arbeitsgruppensitzung noch folgende Vorträge eingereicht: LEBEDEV, T.S.; SAPOVAL, V.I. ; KORCIN, V.A.: Experimentelle Untersuchung der spezifischen Volumendeformation, der Kompressibilität und der Dichte von Gesteinen unter hohem Druck OESBERG, R.-P.: Der elektrische Widerstand von Mineralen und Gesteinen unter hohen Drücken und Temperaturen und der Bau der ·Erdkruste und des oberen Erdmantels TARKOV, A.P.: On the possible density d.ecrease of the upper mantle in the saismic channel zone for Vs VOLAROVIC, M.P.: Apparate und Methoden zur Untersuchung physikalischer Eigenschaften von Gesteinen unter hohen Drücken