Malibu sinkhole near reported Nicolas Cage property exposes coastal erosion risk

A large ground collapse beside a beachfront Malibu property reportedly owned by Nicolas Cage has been linked to coastal erosion, seawall undermining and strong wave action associated with Hurricane Marie.

The City of Malibu received the first report of the collapse on Sea Level Drive at around 5:45am on 8 September. The hole affected a beachfront driveway and extended into the roadway. No injuries were reported, but the city declared a local emergency and issued evacuation orders for 31 properties.

Utility services were also affected. SoCalGas shut off gas service after a leak was reported, while Waterworks District 29 shut off water service to reduce the risk of water main breaks. By the evening of 8 September, the collapse had expanded to an estimated 25 ft to 30 ft deep and approximately 30 ft by 60 ft wide.

Although widely described as a sinkhole, the reported mechanism is more closely linked to coastal erosion and loss of support behind a seawall. Engineering consultants for the City of Malibu said the principal mechanism was undermining of the seawall on a vacant lot between 31626 and 31630 Sea Level Drive due to increased wave action from Hurricane Marie.

Two recent hurricane-related swell events reportedly lowered the beach level by around 4 ft to 5 ft below the bottom of the seawall sheathing. Once the beach material was scoured down, the backfill behind the wall became exposed to wave action. Over time, this removed support from the parking deck and driveway until collapse occurred.

This distinction matters. A classic sinkhole is often associated with subsurface voids, dissolution, collapsed utilities or buried features. In this case, the available information points to a coastal failure mechanism: beach lowering, seawall undermining, backfill erosion and progressive loss of support.

Typical ground conditions below the road are reported to include about 5 ft to 8 ft of artificial road fill, over 10 ft to 15 ft of sandy terrace deposits, with sedimentary bedrock at depths of around 20 ft to 25 ft. In some areas, road fill has been placed over beach sand, with cobbles and bedrock below.

These conditions can be vulnerable where coastal protection is undermined. Once waves reach the backfill behind a seawall, granular material can be washed out, creating voids and reducing support below pavements, driveways and nearby foundations.

The city, homeowners association, property owners, engineers and contractors have been coordinating emergency response, temporary erosion protection, site security and temporary shoring plans. Red tags were issued where distress was observed, and several properties remained affected by evacuation orders, road closure and utility shutoffs.

The near-term objective is to restore limited access once road shoring is installed, remove debris and begin backfilling the collapse area. Permanent repairs will require further engineering review, permitting and coastal protection design.

The Malibu incident shows how rapidly coastal erosion can become an infrastructure and public safety issue. Strong waves, high tides, beach lowering and seawall undermining can turn a local erosion problem into roadway failure, utility disruption and evacuation of nearby properties. With Malibu also preparing for possible strong storms, heavy rain, mudslides and coastal erosion this winter, the event highlights the need for continued monitoring of vulnerable coastal roads, seawalls and beachfront structures.