Last week on PBS there was a show about how the Hawaiian Islands (and any other volcanic islands) are formed. The scary point that they were making was the volcanic flow comes to rest on the sea bed- SAND. And, sooner or later the weight of the island will bear enough on the sand that the island will break off an slide back into the sea- probably causing a massive tsunami that would hit the Americas. The pictures of a mountainside calving off like an iceberg are a preview of coming attractions for Hawaii. True, it may be thousands of years away, but, still... be advised, and plan ahead !