South side of East Rift Zone is moving toward the ocean in much faster rate since M6.9 quake due to volcanic activities.
It is interesting to know that this East Rift Zone is the direction of fissures opened up in Leilani Estate last year. And it is breaking away, and eventually, it is falling to ocean.
That is generally called Hilina Slump.
The larger mass (red line) might be falling down to the ocean than Hilina Slump.
Can you imagine how deep under the water? The mountain and land we can see over the ocean in Island of Hawaii is just like a tip of iceberg. Under the sea, it is really long steep to the bottom of ocean floor.
It will slide 1000m over the sea and 4000m under the sea to the ocean floor. So it will be 5km (3mile) slide to the bottom.
Ben explains GPS displacement. The southern frank part of Kilauea is almost ripping apart toward the ocean.
This movie shows a physics-based computer simulation of a Kilauea Flank Collapse landslide and Mega Tsunami. Local wave heights exceed 300 meters. Such events happen in Hawaii about every 200,000 years.
Mega Tsunami will impact West Coast of US. San Francisco might get 35m (115 foot) tsunami.