This chapter reviews the results of studies of late- and postglacial faults in the Russian part of the Fennoscandian Shield (Kola Peninsula, Karelia, Sankt-Petersburg region). It provides a brief overview and description from north to south of the main seismic lineaments (Murmansk and Kandalaksha) as well as results from a study of some secondary lineaments, individual late- and postglacial faults and seismic dislocations. The obtained data allowed defining a decrease in seismic activity from the Late Glaciation to the present times. It is due to the fading glacial isostatic uplift of the shield and the change of the leading role from the vertically directed forces of glacial isostasy to horizontal compressive strains. Glacial isostasy as a factor giving rise to stresses has nearly exhausted itself by the present time, while the tectonic factor continues to be felt.

The area under study is located in the south-eastern periphery of the Fennoscandian crystalline shield. At present this is a tectonically quiet region without large seismic events. But it is well known that in post-glacial time the Fennoscandian shield was an arena of active postglacial tectonics and large earthquakes. The evidence for such events was found in various parts of Fennoscandia. The traces left by some paleoearthquakes show an undisputed character of large post-glacial faults some tens of kilometres long and of a few meters in displacement. However, some other features left by earthquakes are under discussion. Numerous deformations in bedrock and in soft sediments which can be considered as being due to earthquakes were found in the Russian Karelia. Interpretation of some of these deformation structures can lead to different conclusions about their origin, for example, weathering, cryogenic, glacial, and gravitational factors. One possible way to overcome these difficulties is an integrated study of different types of deformations at key sites, comparison of these with each other and with the tectonic features of the region, and the search for common structural and kinematic features. Another problem is the estimation of parameters of paleoearthquakes. This problem includes the determinations of their location, intensities, magnitudes, and age. The key site under study is located in the northern part of the Karelian Isthmus in the re-activated (during post-glacial time) tectonic zone (the Vuoksi Fault Zone), whose signature in the relief is seen in the form of the straight-line valley of the Vuoksi River. We studied different types of post-glacial seismogenic deformations at this locality. There are seismically induced gravitational and vibrational deformations in solid rock, as well as folds and ruptures in loose sediments. The key site of large deformation examined here includes three zones: 1) the main zone of deformations or the Central Fractured Massif (CFM); 2) the seismically induced colluvial zone; 3) the outer zone of deformations in loose sediments. We have established that all types of deformations are kinematically similar in the CFM and around it (at distances of a few kilometres). A detailed examination of deformations and their spatial and temporal relationships allows us to distinguish three generations of earthquake-induced deformations: 1) Late Glacial, 2) Early Holocene, and 3) Middle to Late Holocene. We estimate the intensities of the respective earthquakes as I=IX, IX, and VII-VIII. Clearly, the intensities decrease from post-glacial to present time, but the recent level of seismicity is unclear and may be much higher than hypothesized. In addition, the evidence for shear kinematics of the fault shows that earthquakes were not only caused by post-glacial rebound, but also resulted from a different tectonic mechanism possibly related to plate tectonics.

The territory of investigations is located in the SE periphery of the Fennoscandian Shield. It served as an arena of periodic significant restructuring of the hydrographic network associated with the filling and discharge of large late-glacial and Holocene basins during the degradation of the Scandinavian ice sheet and in postglacial time. One such restructuring is a sudden change of the Saimaa Lake direction of flow in the middle Holocene from the west to south to the Lake Ladoga basin via the drainage hollow, inherited by modern Vuoksi River valley. Origin of the Vuoksi River is associated with the catastrophic water breakthrough of the Saimaa Lake across the marginal ridge Salpausselka I of about 5.7 cal. kyr BP. This event usually connects with water accumulation and overflow due to non-uniform post-glacial uplift according to modern concepts. The authors propose a great earthquake as the immediate cause of the break waters of Saimaa Lake. This suggestion is based on the study of specific deformations of the rocky riverbed in the area of breakthrough and of the loose deposits in the banks of the Vuoksi River valley downstream. Open cracks and horizontally displaced rock blocks were discovered in the area of the former rapids near town Imatra. Their systematic displacements on the both sides of the rocky gorge indicate the shear kinematics of fault zone. Different types of deformations had occurred in loose sediments of the low terraces (3-4 m) in the Vuoksi River valley and 20-30 km below the headwaters. In three studied stratigraphic sections the three cardinal different types of deformations were discovered: 1) normal fault with vertical displacements, 2) tectonic inclination, and 3) traces of catastrophic mudflow. The time diapason of the terrace forming (and of the corresponding deformations) is determined of 8.3 to 1.8 cal. kyr BP (by the ages of adjacent terrace levels), which corresponds to the origination time of the Vuoksi River. The earthquake, which presumably was a trigger for the formation of the Vuoksi River, was generated by the activation of ancient fault zone, manifested in the crystalline foundation. Periodic post-glacial tectonic activity of this zone is revealed in traces of strong seismic events both in the bedrock (initial emergence of the gorge, its renewal during the breakthrough), and in loose deposits (deformations in different levels of terraces).

Mikhail Gzovskii was a scientist of diverse abilities. After overcoming the contradictions in the perception of nature by a geologist and mathematical physicist, he showed the capacity for both intuitive and deterministic thinking and the abilities of a tectonic geologist, a geophysicist, and a specialist in mechanics. He combined the qualities of a superb field investigator, a serious experimenter, a theoretician capable of broad generalizations, and a practitioner who always sought to put his results into practice. Along with his great scientific talent as a researcher went truly extraordinary efficiency and energy, owing to which, after framing the logic of his studies, he brilliantly conducted them, and, having analyzed their results, he advocated them with the clarity of a philosopher, the accuracy of a mathematician, and the conclusiveness of an experimenter.

Based on new versions of the local earthquake catalog and morphostructural map and using repeated leveling data, earthquakes are compared with structural heterogeneities and active faults. They are found to be mutually consistent. Related problems of seismic hazard are discussed.

This paper relates some facts about abnormal animal behaviour prior to several Armenian earthquakes. The catastrophic Spitak, northern Armenia, earthquake of 7 December 1988, M = 7, I0 = X, was preceded by extensive occurrences of abnormal animal behaviour. Proof was established by questioning residents in the area and by distributing specially prepared questionnaires shortly after the event. Approximately 200 reports from 50 sites were examined. The raw data recorded included lists of different types and locations of species that have shown abnormal responses to an impending earthquake, distribution of anomalous occurrences over the area, and precursor times. It is concluded that specially conducted observations of animal behaviour as a possible premonitory phenomenon is both useful and necessary.

The paper presents new data on seismicity of the eastern and northern framing of the Kerch peninsula. Until quite recently the northern coast of the peninsula has been erroneously considered to be seismic-dangerous. The revision of these notions is not only of cognitive but also of practical importance, since the Crimean APP has been built on the Kazantin Cape in the vicinity of Lake Akatash.