The worst case scenario - a strong earthquake strikes California, disabling the carrier hotel at One Wilshire, disrupting operations at submarine cable landing stations in both the Los Angeles area and central California, with a resulting tsunami hitting Hawaii, Guam, the Philippines, Taiwan, and Japan.
Communications are severed to most of the South Pacific, and severely degraded to allow for only emergency services and national defense usage within the west coast of the United States. Financial and government communications are disrupted and severely limited into Japan, Hong Kong, and China.
Telecom carriers in Singapore, Japan, Hong Kong, China, and Australia work frantically to restore cable, Internet, and telecom capacity from the Pacific submarine cable systems through the Indian Ocean to Europe and the US east coast. Seattle and San Francisco still have some connectivity, however cable systems from Grover Beach to San Diego are inoperable, limiting connections to those which were designed with automatic rerouting through North Pacific cable systems.