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The knowledge of early earthquakes in South Africa is based, as in other parts of the world, on macroseismic phenomena observed by different people and reported by old chronicles, local papers, travelling reports and scientific communications. Seismic histories are usually compiled from three main sources of information: instrumental, historical and geological. Instrumental data offers the best and most complete information about earthquakes. Instrumental information must be supplemented by historical and geological evidende as the period of time covered by seismometers is too short to provide a basis for unqualified geological conclusions. Geology itself and surface indications offer permanent, though complicated evidence of past seismic activity.
For more information regarding the seismicity in South Africa please go to our Points of Interest page Seismic History of the southwestern Cape Province Earth tremors have been recorded from the southwestern Cape since 1620. Between then and 1966 the area experienced at least 43 shocks, 10 probably exceeding 4,5 in magnitude. Of these latter, 4 evidently exceeded 5,1. Documentation (old journal extracts and photographs etc.) regarding some of the events listed below are available by clicking on the highlighted dates. Pages may download slowly. | Date | Local Time
(GMT) | Summarised description of observations | Deduced intensity (Modified Mercalli Scale) | Deduced magnitude (Richter scale) | Source | 1620 | 06:00-07:00 | Two startling thunderclaps like cannon shots while ship was becalmed near Robben Island for several days | III-IV | ± 4 | Strangman, 1936 | 1690 | ? | Slight shock felt | III | 3,5-4 | Leibbrandt, 1896 | 4 Sep 1695 | 19:00-20:00 | Loud noise like thunder, earth trembled, no damage, no injury | IV | ± 4,5 | Leibbrandt, 1896 | 11 Jan 1696 | Afternoon | Slight trembling, no noise | III | 3,5-4 | Theal, 1922 | 5 Sep 1739 | ± 02:00 | Shock which lasted only few minutes, loud noise like thunder, no damage | III-IV | ± 4 | Von Buchernröder, 1830 | 28 Aug 1749 | Dawn | Two shocks in quick succession, thunderous noise, no damage | III | 3,5-4 | Theal, 1922 | 14 Jul 1766 | ± 02:00 | Strong tremor, noise like thunder, at Simonstown, hospital beds knocked against wall, people frightened, only damage caused was that old cracks in walls and gables opened again | IV-V | 4,3-4,8 | Von Buchernröder, 1830 | 4-12 Dec 1809 | 22:08 | Three strong quakes, second most violent on 4th, loud reports, everybody frightened, fled to streets, tremendous noise continuous few minutes, no wave-like motion, all buildings suffered numerous cracks, water spouts etc. in places. Another 4 tremors from 5th to 12th, some strong | VI-VIII | 6,1 | Von Buchernröder, 1830 | 26 Dec 1810 | ? | Slight trembling of earth felt only at Genadendal | III | 3,5-4 | Burchell, 1822 | 7 Jan 1811 | 06:00 | Slight shock experienced by only few people, did not awaken Burchell | II-III | ± 3,8 | Von Buchernröder, 1830; Burchell, 1822 | 2 Jun 1811 | 11:00 | Two loud reports and shocks, second about same violence as first shock of 4 Dec 1809, strange unusual motion felt, last 5-6 seconds, everybody ran outside, walls cracked, some unsafe, urns again tumbled from parapets | VII | 5,5-6 | Von Buchernröder, 1830; Burchell, 1822 | 19 Jun 1811 | A few minutes before 10:00 | Slight shocks, hollow rumbling sound and strong trembling, some damage to buildings, lasted few seconds | V | 4,8 | Von Buchernröder, 1830; Burchell, 1822 | 24 Jun 1819 | ? | Earthquake felt at Piketberg, did not extend as far as Malmesbury or Berg River | III | ± 4 | Forbes, 1949 | 14 Apr 1826 | 07:00 | Slight shock | III | ± 4 | Von Buchernröder, 1830 | Early in 1826 | ? | Severe tremor at Saldanha Bay, not felt at Cape Town | VI? | ± 5? | Teenstra, 1943 | 11 Nov 1835 | 03:48 | Smart shock, rumbling sound lasted 30 seconds, residents awakened and alarmed, furniture moved, water shaken from glass, windows rattled, no damage to buildings | V | 4,8 | Maclear, 1935 | 14 Aug 1857 | 23:30 | Slight shock, gentle trembling which grew in intensity at Cape Town, houses intensely shaken second or two, overall duration 25-30 seconds. Shock markedly more severe in some country districts eastwards, considerable damage to buildings there | IV | ± 4,5 | Morton, 1857 | 28 May 1902 | 23:45 | Distinct shock, beds rocked, shaking of doors and windows, animals reacted strangely, lasted only few seconds, walls cracked in few houses | IV-V | 4,8 | Stewart, 1902 | 6 Jul 1911 | 22:15 | Dull booming sound, distinct vibration at Oudtshoorn | III-IV | ± 4 | Finsen, 1950 | 20 Feb 1912 | 15:04 | Epicentre near Koffiefontein, felt all over South Africa, many farm buildings completely destroyed. Epicentre: 29,5°S, 25°E | VIII | ± 6 | Finsen, 1950; Gutenberg and Richter, 1965 | 13 Aug 1920 | 09:05 | Tremor distinctly felt, windows rattled, water agitated in glass | IV | 4,5 | Finsen, 1950 | 4 Dec 1920 | 07:52 | Very strong quake in the sea felt at Cape Town, George, Port Elizabeth. Epicentre: 39,0°S, 21°E | IV | 6,2 | Finsen, 1950; Gutenberg and Richter, 1965 | 19 Feb 1921 | ? | Strong, mainly felt at Vanrhynsdorp | V | 4,8 | Magnetic Observatory, Hermanus | 9 Oct 1921 | 15:20 | Strong, shook houses and rattled windows, slight damage to houses at Tulbagh, lasted 8-10 seconds | VI | ± 5,0 | The Argus, 10 Oct 1921 | 1924 | 07:40 | Slight tremble only felt locally | III | ± 4 | Magnetic Observatory, Hermanus | 11-13 Aug 1926 | ? | Series of tremors felt at Darling | III-IV? | ± 4? | Magnetic Observatory, Hermanus | 18 Nov 1932 | 09:54 | Fairly strong, felt only at Cape Town | VI | ± 5? | Magnetic Observatory, Hermanus | 19 Aug 1937 | 16:00 | Tremor lasting few seconds, Darling | IV | ± 4,5 | Finsen, 1950 | 1940? | ? | Tremor felt at Wolseley | IV | ± 4,5 | Die Burger, 29 Aug 1963 | 23 Oct 1941 | 20:30 | Tremor in sea just west of Bitterfontein | V | 4,8 | Finsen, 1950 | 24 Aug 1944 | Night | Tremor at Beaufort West | II-III | 3 | Finsen, 1950 | 27 Feb 1947 | 12:19 | Two very noticeable earth tremors felt at Cape Columbine and Paternoster but did not extend to Saldanha Bay | V | 4,8 | Finsen, 1950 | 19 Nov 1950 | ? | Slight tremor at Cape Town | III | 4,2 | Magnetic Observatory, Hermanus | 26 Feb 1952 | ? | Slight tremor felt at Swellendam | III | 4,2 | Magnetic Observatory, Hermanus | 20 Sep 1957 | 05:38 | Slight tremor felt at Cape Town | III | 4,2 | Magnetic Observatory, Hermanus | 30 Sep 1957 | ? | Slight tremor felt at Cape Town | III | 4,2 | Die Burger | 29 Aug 1960 | 07:35 | Tremor felt all over Boland and in Cape Town, people awakened, beds rocked, no sound, lasted ± 15 seconds | IV-V | 4,3-4,8 | The Argus, 29 Aug 1960 | 27 Aug 1963 | 02:48 | Sharp shock felt all over Western Cape, most severe De Doorns-Worcester-Ceres area, woke and frightened people, buildings heaved, windows and furniture and roof rattled, few walls cracked, duration 90 seconds. | VI | 5,0 | The Argus, 28 Aug 1963 | 18 Sep 1963 | 01:40-04:30 | Twelve loud rumbles with trembling, little damagae, mainly felt Karoopoort-Ceres | IV-V | 4,3-4,8 | Die Burger, 19 Sep 1963 | 21 Feb 1964 | ? | Shock felt all over Peninsula | IV | 4,3 | Die Burger | 28 Sep 1965 | ? | Shock mainly felt at Oudtshoorn | IV | 4,3 | Die Burger | 1 Mar 1966 | 02:04 | Shock felt all over Peninsula | IV | 4,3 | Die Burger, 1 Mar 1966 | 12 Sep 1969 | ? | Strong shock felt all over Western Cape from Cape Town to Mossel Bay, George; especially at Oudtshoorn: 33,5°S, 21,9°E (USCGS) | IV-V | 5,4 | Die Burger, 12 Sep 1969; USCGS Bulletin | 29 Sep 1969 | 22:03 | Marked tremor all over Western Cape, especially at Ceres, Tulbagh, Wolseley; extensive damage, deaths, sandboils; water spouts at Ceres; extensive cracks, etc. | VIII-IX | 6,3 | Magnetic Observatory, Hermanus; Die Burger; The Argus; USCGS Bulletin | 1 Oct 1969 | ? | Slight shock Tulbagh and vicinity | III? | 4,2 | The Argus | 6 Oct 1969 | 12:28 | Slight tremor felt at Sea Point and vicinity | III? | 4,2 | The Argus | 7 Oct 1969 to 13 Apr 1970 | | In Tulbagh/Ceres area 10 tremors were felt on 4 Mar 1970; at Ceres at 01:00 a readning of 4 Richter Scale. In Peninsula 2 slight tremors were felt. | III-IV | ± 4,2 | The Argus | 14 Apr 1970 | 21:10 | Marked tremor at Ceres/Tulbagh, felt all over Western Cape; trembling and further damage | VII | 5,7 | Magnetic Observatory, Hermanus; The Argus; USCGS Bulletin | 15 Apr 1970 to 19 Sep 1971 | | According to newspapers very few tremors of great magnitude. Tremors barely felt in the Ceres area during this period - total 10; in Peninsula - 3 | | | The Argus; Die Burger | 19 Sep 1971 | 09:40 | Marked tremor near Ceres-Tulbagh-Porterville, no damage, lasted few seconds | IV | ± 4 | Die Burger, 20 Sep 1971; Station PRE of the WWSSN | 28 Sep 1971 | 17:03 | Southwestern Cape Province | IV-V | 4,8 | Station PRE of the WWSSN | References: Theron, J.H., 1974, The earthquake of 29 September 1969 in the southwestern Cape Province, South Africa. Seismologic Series 4, Geological Survey, p. 12-18. Fernandez, L.M., and Guzman, J.A., 1979, Seismic history of Southern Africa. Seismologic Series 9, Geological Survey, 38 pp.
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