Cliff erosion was investigated at the coasts around Point Loma in San Diego and Del Mar areas in California. On these coasts, installation of countermeasures against cliff erosion is rare in contrast to the cliff coasts in Japan. On Japanese coasts, concrete armor units are usually installed to protect coastal cliff and this causes decrease in sediment supply from the cliff, which induces beach erosion on the down coast. This gives one of the reasons for extension of artificial coastline in Japan. Overall stability of the sandy beach including cliffy coast as a sand supply source should be deeply considered.
