Uno wrote:
It looks almost strait line of spider. It should not be formed by slow
gravity flow. The movment must be very fast and strong in multi-directions.



Uno:

Some guesswork. . . .

Could the radial lines be lava tubes formed by the molten rock spray
that drained back into the crater depression?

If they were tubes they were enormous in size, both in length and width.
Several graben join together into larger ones nearer the crater. The top
covers of tubes may have melted away in the hot environment, and the
eroding flows may have formed flat bottomed river grooves in the grit.
On the other hand, if tubes were formed the slenderness ratios of the
shells may not have enabled the support of the structures.

Ralph Hertle