Hypsometric changes in urban areas resulting from multiple years of mining activity

Abstract

The impact of multiple years of underground mining of minerals on changes in the elevation of an urban area has been evaluated using the case study of Bytom in southern Poland. Between 1883 and 2011, that city experienced changes in absolute minimum (from 250.0 to 243.0 m a.s.l.) and maximum (from 340.0 to 348.4 m a.s.l.) elevations. During that period, the difference between minimum and maximum elevations increased from 90.0 to 105.4 m. The consequence of underground mining has been the formation of extensive subsidence basins with a maximum depth of 35 m. Where the terrain became raised, its elevation rose most commonly by 1.1 m to 5.0 m, with maximum increase in elevation caused by human activity amounting to 35 m. The rate of anthropogenic subsidence in the city between 1883 and 2011 averaged 43 mm/year (5.5 m over the study period).

Figure 1

Study area location: 1—water courses and water reservoirs; 2—major cities.

Figure 2

Land relief within the city of Bytom at the end of the nineteenth century (within present-day city limits): 1—city boundary; 2—absolute elevation [m a.s.l.].

Figure 3

Land relief within the city of Bytom at the end of the twentieth century (within present-day city limits): 1—city boundary; 2—absolute elevation [m a.s.l.].

Figure 4

Changes in relative elevation within Bytom between 1883 and 1994: 1—city boundary; 2—elevation changes at selected height control points; 3—elevation changes within city limits.

Figure 5

Land subsidence in the Bytom area in the years 1883–2011: 1—contemporary city limits; 2—built-up areas where mining damage and demolitions occurred; 3—built-up areas (as at 1883); 4—built-up areas (as at 1934); 5—built-up areas (as at 1994); 6—built-up areas (as at 2011); 7—range of land subsidence in the period 1883–2011; 8—city districts.

Figure 6

Examples of damage to Bytom’s urban fabric as a consequence of land subsidence (photo: M. Solarski).

Figure 7

Changes in Bytom’s relief intensity in the nineteenth and twentieth centuries: A—changes in relative elevation from the late nineteenth century to the late twentieth century; B—variation in relative elevation in the late nineteenth century; C—variation in relative elevation in the late twentieth century; 1—city boundary; 2—magnitude of change in relative elevation from the late nineteenth century to the late twentieth century; 3—variation in relative elevation from the late nineteenth century to the late twentieth century.