9
$\begingroup$

Messing around on Google Earth recently I noticed a number of striations in the Eastern Pacific. These appear in an East-West orientation and seem to start on the North and South American continental shelves, and extend for roughly half the Pacific Ocean. For example one of these striations start in Santa Rosa Island off California and ends at Hawaii. These striations also appear to be roughly equally spaced at 8 degree intervals. The North and South American striations are angled with respect to each other and seem to converge at roughly Tahiti.

What causes these? I'm a fascinated novice.

EDIT

Some images to make things clearer (North Pole is top left):

Note the regularly spaced East-West parallel striations starting from the Equator and stepping north. In fact the striation on the Equator covers the entire Pacific.

enter image description here

Here a closer shot also shows fainter striations fanning out from Los Angeles:

enter image description here

$\endgroup$
  • $\begingroup$ It would really help if you posted a screenshot of exactly what you are asking about, because there are lots of natural linear features too, for example transform faults in the crust. If there are too many features, perhaps you could label the ones you're interested in. $\endgroup$ – kwinkunks Sep 16 '15 at 16:32
  • $\begingroup$ Thanks for the edit — that made all the difference. I edited my answer. $\endgroup$ – kwinkunks Sep 17 '15 at 0:04
5
$\begingroup$

They are fracture zones.

I've annotated your image with the names of these very long, tectonically important features. They even have names, such as the Mendocino Fracture Zone:

Fracture zones in the northeastern Pacific

I also labelled some survey tracks (rather subtle, very straight, very regular in width), which are data artifacts — these are the things you noticed radiating from the vicinity of Los Angeles.

There are yet other types of linear feature on the sea floor:

Images from Google Maps. Note: I edited this answer substantially after the OP clarified the question... and I learned about the difference between transform faults and fracture zones.

$\endgroup$
  • $\begingroup$ I would agree that what I'm seeing are more likely due to these transform faults, considering their length and width. I just wonder what causes their extreme length and regular spacing. $\endgroup$ – Guillermo Phillips Sep 16 '15 at 21:16
3
$\begingroup$

Several data sources with very different resolutions are combined in such maps, for example gravity measurements from satellites and echo sounding (there is also a wikpedia article on that, I can only post 2 links) on board ships.

"[L]inear artifacts such as artificial 'ridges' and 'troughs' " are artifacts from combining high resolution data from ship tracks which tends to be available in the pattern you observed with low resolution data from gravimetry.

$\endgroup$
  • $\begingroup$ I was wondering if it was real or artifacts of data. I guess we shouldn't believe everything we see! $\endgroup$ – Guillermo Phillips Sep 16 '15 at 14:05

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.