Sentence: Widely previously interpreted as precursory activity to the 1906 earthquake, they have been found to have a strong seasonal pattern and have been postulated to be due to large seasonal sediment loads in coastal bays that overlie faults as a result of the erosion caused by hydraulic mining in the later years of the California Gold Rush.
Entities: entity1: hydraulic mining; entity2: erosion
Relationship: Cause-Effect