fault line above grjotagja cave - geothermal hot spring, lake myvatn, northern iceland

rock geology terrain formation soil bedrock plateau outdoors europe scenery volcanic natural view outdoor beautiful tourism grjotagja grjótagjá cave lake myvatn iceland landscape travel stream nature lava mývatn geothermal hot spring krafla volcano mame thrones game jon snow wildling ygritte duncan autumn barren desert fault line northern october