Coastlines usually have lots of inlets, bays, rivers, etc., things that disrupt straight lines on the map, but that’s not the case in this area. Much of Malibu is sandwiched between the coastline and a set of hills to the north. Of course, if there are hills in the area, that probably means there’s a fault.
The Malibu Coast Fault is a thrust fault that sits right along the coastline in Malibu, running for about 30 kilometers almost due east-west. This fault dips to the north; the rocks to the north are being pushed up over the rocks to the south. To the north, there sits an east-west striking mountain range uplifted by this fault, the Malibu Hills, which transitions smoothly into the Santa Monica Mountains and the Hollywood Hills closer to the L.A. basin
This photo is of the one feature in Malibu that isn’t like the other. This spot, known as Point Dume, is the one spot in Malibu where the land juts out into the sea. It’s readily visible on maps and satellite photos; it sticks out several kilometers into the ocean, with flat terraces on the top.
Point Dume is a location where the Malibu Coast Fault has broken into several sections, called “splays”. To the east and west, those strands join back together to form a single fault, but here, there is land trapped in the middle of multiple fault segments. The trace of one fault strand can actually be seen in this image; look closely at the rocks on the point. Just above the wave line, there is a color change between dark rocks at the base and lighter brown rocks above. That color change marks one strand of the Malibu Coast Fault.
The presence of this fault means that the entire area sits under a seismic threat. This system is comparable to the one on which the 1994 Northridge earthquake happened; a thrust fault associated with the formation of the L.A. Basin and the mountains around it, so large, damaging earthquakes are possible. Yet, given its location and climate, it is clearly in high-demand for real estate and recreation.
If there wasn’t a state park to protect it, and you didn’t know about the fault, Point Dume might seem like a great place to put a house. Imagine the house you could build there; big glass windows overlooking the Pacific Ocean on every side.
Of course, that kind of house isn’t hard to imagine. In fact, if you go to a movie theater this weekend, I believe you get to see that very house crash into the ocean. Point Dume is the site of Tony Stark’s house in the Marvel Movie Universe. (I promised another Iron Man 3 post, here it is).
Point Dume has served as the location for other Hollywood filming, including the penultimate scene in “Planet of the Apes”. The beach to the left of this image was used, with a matte painting employed to replace the rocks with the Statue of Liberty. But for this weekend, this is Stark’s mansion.
There isn’t really a house on Point Dume, obviously. It’s a state park, so the land itself is moderately protected and available for public use. The house in the movies is completely done on sound stages and computers. And frankly, that might well be a good thing; I don’t think you could convince me to build a house sitting tens of meters above the Malibu Coast Fault. But, if you’re going to be a multi-billionaire industrialist superhero, and you want a great view…seems like Point Dume is a good choice. Anyway, that’s it for me writing for today, I’ve got a movie to go see.
Photo Credit (Nonprofit use): Bruce Perry, Department of Geological Sciences, CSU Long Beach
Malibu Coast Fault:
LA Basin fault maps:
1990 Article on Malibu Coast Fault activity:
Tony Stark’s house, Marvel Universe Wiki: