Halvor H. Sandblost is in the 1910 US census for Lane Co. Oregon.He is listed as 54 years old, born Norway, and his year of immigration is almost illegible reading either 1875, 1878, or 1870something.Married 28 years, his wife listed as mother of 6, 4 still surviving in 1910.
Sandblost would NOT be a surname in Norway but would be the name of a place.Probably the place where Halvor was born or had other connection - such as family history and/or living there for a number of years.
If his father 'had the same name' then Halvor would have been known as Halvor Halvorsen in Norway.Sandblost could have been added as an additional identifier much like an address.Many Norwegian emigrants chose a farm name as an Americanized surname in the new country.
Searching familysearch.org for any child born of a Halvor Jensen and Olava Hansdatter in Norway between 1852 and 1858 results in the following - https://familysearch.org/pal:/MM9.1.1/VW2P-6LS
So Halvor's birth/baptism record is found in Kvernes church books of Møre og Romsdal.It lists him as born out of wedlock to bachelor Halvor Jensen and the unmarried woman Olava Hansdatter.The first baptismal witness listed on that record is the same man that is the head of household seen above in the 1865 census where Halvor was living.The Kvernes record lists his birth date as 8 Oct 1854. http://www.arkivverket.no/URN:kb_read?idx_kildeid=2282&idx_id=2282&uid=ny&idx_side=-23http://www.arkivverket.no/URN:kb_read?idx_kildeid=2282&idx_id=2282&uid=ny&idx_side=-23