Oshima

Google Earth Placemark
  • Country
  • Subregion Name
  • Volcano Type
  • Last Known Eruption
  • 764 m
    2506 ft
  • 34.721°
  • 139.398°
  • Elevation
  •  
  • Latitude
  • Longitude

There are no activity reports for Oshima.



 Available Weekly Reports


There are no Weekly Reports available for Oshima.

Summary of eruption dates and Volcanic Explosivity Indices (VEI).

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
1990 Oct 4 1990 Oct 4 Confirmed 2 Historical Mihara-yama (1987 summit crater)
1987 Nov 16 1988 Jan 27 Confirmed 2 Historical Mihara-yama
1986 Nov 15 1986 Dec 18 Confirmed 2 Historical Mihara-yama, N part and NW of caldera
1974 Feb 28 1974 Jun 20 Confirmed 1 Historical Mihara-yama
1971 Apr 5 1971 Apr 5 Confirmed 1 Historical Mihara-yama
1970 Jun 30 1970 Nov 12 Confirmed 1 Historical Mihara-yama
1970 Jan 26 1970 Jan 31 Confirmed 1 Historical Mihara-yama
1969 Jan 19 1969 Jul Confirmed 1 Historical Mihara-yama
1968 Jul 28 1968 Jul 28 Confirmed 1 Historical Mihara-yama
1968 Jan 19 1968 Jan 19 Confirmed 1 Historical Mihara-yama
1967 May 1967 Aug Confirmed 1 Historical Mihara-yama
1965 Nov 25 1966 Jun 13 Confirmed 1 Historical Mihara-yama
1962 Jan 1965 May Confirmed 1 Historical Mihara-yama
[ 1961 ] [ Unknown ] Uncertain     Mihara-yama
1959 Oct 1960 Nov Confirmed 1 Historical Mihara-yama
1959 Jan 1959 Jan Confirmed 1 Historical Mihara-yama
1958 Apr 17 1958 Jun 13 Confirmed 1 Historical Mihara-yama
1957 Aug 1957 Dec Confirmed 1 Historical Mihara-yama
[ 1956 Aug 25 ] [ 1956 Aug 26 ] Uncertain 1   Mihara-yama
1956 Jan 3 1956 Jan 6 Confirmed 1 Historical Mihara-yama
1953 Oct 5 1954 Feb 8 Confirmed 1 Historical Mihara-yama
1950 Jul 16 1951 Jun 28 Confirmed 2 Historical Mihara-yama, south rim
1940 Aug 18 1940 Aug 19 Confirmed 1 Historical Mihara-yama
1939 Sep 1 1939 Sep 16 Confirmed 1 Historical Mihara-yama
1939 Feb 1939 Feb Confirmed 1 Historical Mihara-yama
1938 Aug 11 1938 Aug 11 Confirmed 1 Historical Mihara-yama
1937 Jul 17 1937 Aug Confirmed 0 Historical Mihara-yama
1935 Apr 26 1935 May 6 (?) Confirmed 0 Historical Mihara-yama
[ 1934 Sep ] [ Unknown ] Uncertain     Mihara-yama
1934 Apr 15 1934 Apr 25 (?) Confirmed 0 Historical Mihara-yama
1933 Oct 14 1933 Nov Confirmed 0 Historical Mihara-yama
1928 Aug 7 1928 Aug 8 Confirmed 2 Historical Mihara-yama
1922 Dec 8 1923 Jan 30 Confirmed 1 Historical Mihara-yama
[ 1920 ] [ Unknown ] Uncertain     Mihara-yama
1919 May 18 1919 Dec 23 Confirmed 0 Historical Mihara-yama
1915 Oct 10 1915 Oct 25 (?) Confirmed 2 Historical Mihara-yama
1914 May 15 1914 May 26 Confirmed 2 Historical Mihara-yama
1912 Feb 23 1913 Jan 25 Confirmed 1 Historical Mihara-yama
1910 Dec Unknown Confirmed 1 Historical Mihara-yama
1876 Dec 27 1877 Feb 5 Confirmed 2 Historical Mihara-yama
1870 Unknown Confirmed 2 Historical Mihara-yama
[ 1868 Dec 31 ± 365 days ] [ Unknown ] Uncertain     Mihara-yama
1846 Unknown Confirmed 2 Historical Mihara-yama
[ 1837 ] [ 1838 ] Uncertain 2   Mihara-yama
[ 1827 ] [ Unknown ] Uncertain     Mihara-yama
1822 1824 Confirmed 2 Historical Mihara-yama
1821 (?) Unknown Confirmed 3 Varve Count Yephra layer Y0.8
1803 Sep 26 (?) 1803 Nov 14 Confirmed 2 Historical Mihara-yama
1792 Unknown Confirmed 2 Historical Mihara-yama
1789 Unknown Confirmed 2 Historical Mihara-yama
1783 1786 Confirmed 2 Historical Mihara-yama
1777 Aug 31 1779 Confirmed 3 Historical Mihara-yama & flanks, Tephra layer Y1
1695 Apr 12 (?) Unknown Confirmed   Historical
1684 Feb 14 1690 Confirmed 3 Historical Tephra layer Y2
1637 Aug 26 1638 Apr Confirmed   Historical
1634 Unknown Confirmed   Historical
1623 Unknown Confirmed   Historical
1612 Oct 15 ± 180 days Unknown Confirmed   Historical
1600 Oct ± 180 days Unknown Confirmed   Historical
1552 Oct 7 1552 Oct 15 Confirmed 3 Historical
1471 (?) Unknown Confirmed 2 Varve Count Tephra layer Y3.8
1442 Aug 1443 Confirmed   Historical
1421 May 14 Unknown Confirmed 4 Historical Summit, S flank, Tephra layer Y4
1416 Sep 2 1417 (?) Confirmed 2 Historical Tephra layer 4.2
1415 May 21 Unknown Confirmed   Historical
1338 Sep 15 ± 5 days 1338 Nov 15 ± 5 days Confirmed 3 Historical Tephra layer 5
1307 (?) Unknown Confirmed 3 Varve Count NW flank, Tephra layer Y5.2
1245 (?) Unknown Confirmed 1 Varve Count Tephra layer Y5.6
1183 (?) Unknown Confirmed 4 Varve Count Tephra layer Y6
[ 1112 Nov 18 ] [ 1112 Dec 26 ± 5 days ] Uncertain    
[ 936 ] [ Unknown ] Uncertain    
886 Jun 29 (?) (?) Unknown Confirmed 4 Historical Tephra layer N1.0?
854 Sep 14 (?) (?) 856 (?) Confirmed 4 Historical Tephra layer N2.0?
838 Aug (?) (?) Unknown Confirmed 3 Historical Summit, SE flank, Tephra layer N3.0
822 (?) Unknown Confirmed 3 Varve Count Tephra layer N3.2
713 (?) Unknown Confirmed 3 Varve Count Summit, N & S flanks, Tephra layer N4
700 (?) Unknown Confirmed 3 Varve Count Tephra layer N4.2
684 Nov 29 (?) Unknown Confirmed   Historical
680 (?) 681 Mar 26 (in or after) Confirmed 4 Historical Tephra layer N4.4?
654 (?) Unknown Confirmed 3 Historical Tephra layer N4.6?
625 (?) Unknown Confirmed 3 Varve Count Tephra layer N4.8
600 (?) Unknown Confirmed 3 Varve Count Tephra layer S1
580 (?) Unknown Confirmed 3 Varve Count Tephra layer S1.5
340 ± 200 years Unknown Confirmed 4 Radiocarbon (corrected) Summit and east flank, Tephra layer S2
250 ± 100 years Unknown Confirmed 3 Tephrochronology Tephra layer O1
150 ± 50 years Unknown Confirmed 3 Radiocarbon (corrected) Tephra layer O2
150 BCE (?) Unknown Confirmed 3 Tephrochronology Tephra layers O4, O3
600 BCE ± 500 years Unknown Confirmed 3 Tephrochronology Tephra layers O9 to O5
900 BCE ± 100 years Unknown Confirmed 2 Radiocarbon (corrected) SE flank, Tephra layer O10
1050 BCE ± 200 years Unknown Confirmed   Tephrochronology Tephra layers O13 to O11
1200 BCE (?) Unknown Confirmed   Tephrochronology Tephra layer O14
1450 BCE (?) Unknown Confirmed   Tephrochronology Tephra layer O15
2550 BCE (?) Unknown Confirmed   Tephrochronology Tephra layers O29 to O16
3650 BCE (?) Unknown Confirmed   Tephrochronology Tephra layer O30
3750 BCE (?) Unknown Confirmed   Tephrochronology Tephra layer O31
4000 BCE ± 300 years Unknown Confirmed   Tephrochronology Tephra layers O32-2, O32-1, and O32
4250 BCE (?) Unknown Confirmed   Tephrochronology Tephra layer O34
4450 BCE (?) Unknown Confirmed   Tephrochronology Tephra layer O35
4920 BCE ± 500 years Unknown Confirmed   Tephrochronology Tephra layers Osb37-2, Osb36-1
5450 BCE ± 75 years Unknown Confirmed   Tephrochronology Tephra layers Osb37-4, Osb37-3
5550 BCE (?) Unknown Confirmed   Tephrochronology Tephra layer Osb37-5
6050 BCE ± 500 years Unknown Confirmed   Tephrochronology Tephra layers Osb39-2 to Osb38-1
6550 BCE (?) Unknown Confirmed   Tephrochronology Tephra layer O40
6650 BCE (?) Unknown Confirmed   Tephrochronology Tephra layer O41
7150 BCE ± 500 years Unknown Confirmed   Tephrochronology Tephra layers O43, O42
7650 BCE (?) Unknown Confirmed   Tephrochronology Tephra layer O44
8050 BCE ± 500 years Unknown Confirmed   Tephrochronology Tephra layers O46, O45
8450 BCE (?) Unknown Confirmed   Tephrochronology Tephra layer O47

Oshima volcano in Sagami Bay, east of the Izu Peninsula, is the northernmost of the Izu Islands. The broad, low stratovolcano forms an 11 x 13 km island and was constructed over the remnants of three dissected stratovolcanoes. It is capped by a 4-km-wide caldera with a central cone, Mihara-yama, that has been the site of numerous historical eruptions. More than 40 parasitic cones are located within the caldera and along two parallel rift zones trending NNW-SSE. Although Oshima is a dominantly basaltic volcano, strong explosive activity has occurred at intervals of 100-150 years throughout the past few thousand years. Historical activity at Oshima dates back to the 7th century AD. A major eruption in 1986 produced spectacular lava fountains up to 1600 m height and a 16-km-high subplinian eruption column; more than 12,000 persons were evacuated from the island.