In an unexplored basin, extrapolation from known hydrocarbon-producing trends is ideal. However, along transform margins such extrapolations are difficult, owing to lateral displacement between individual blocks on both regional and local scales. An example of this is the relationship between the onshore and offshore Santa Maria basins, which are separated by the Hosgri fault.

Stratigraphic packages have been used widely to approximate amounts of displacement. Lower Miocene volcanics in the offshore Santa Maria P-060-Oceano well may correlate with onshore outcrops, located across the Hosgri fault, 30 mi (48 km) to the east and 45 mi (72 km) to the south, near Point Arguello. Additionally, lower Miocene volcanics also are present in two exploratory wells across the Hosgri fault, 10 mi (16 km) to the east and 25 mi (40 km) to the north, near Point Buchon. These are the Honolulu-Tidewater U. S. L. Heller Lease 1, with 4,722 ft (1,440 m) thickness of volcanics, and the Tidewater Motadoro 1, with 3,873 ft (1,180 m) of lower Miocene volcanics. These wells provide two volcanic sections onshore to tie with the offshore volcanics.

Originally, the lower Miocene volcanics now situated in the northern and southern extremities of the Santa Maria area, may have been joined near the midpoint of their present positions. As the onshore basin pulled apart, the volcanics were divided and transported in opposite directions. Synchronous pull-apart movements occurring in the offshore kept pace with the adjacent onshore. Alternatively, significant intrusive pathways may have opened in the later stage of basin development, allowing igneous material to migrate vertically. These pathways have been termed "leaky" transforms in the literature. Neither of these models necessitates significant lateral displacement once the onshore and offshore basins formed.

Onshore the middle Miocene Monterey Formation and upper Miocene to Pliocene Sisquoc Formation correlate well with equivalent chronostratigraphic units in the offshore P-060-Oceano well, implying that relatively minor lateral displacement has occurred since the middle Miocene. If the offshore basin history is similar to that of the onshore its petroleum potential may approximate that of the onshore, which has been projected to produce 900 million bbl of oil.

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