中文|English  |
设为首页 | 加入收藏
Emergency Alerts
The U.S. Emergency Alert System’s Features and its Comparison with the Emergency Broadcast System of China
2017-10-19 12:05:00 gdemo.gov.cn

The Emergency Alert System (EAS) is established by the U.S. government to provide emergency information service to the American public by means of radio and television coverage. The EAS was originally designed to enable the President of the United States to immediately send out alert notifications during a national emergency. In practice, it is also used to release non-federal emergency information. Since its introduction in 1997, the EAS has never sent any presidential notification nationwide; but it has been used by governments at lower levels to send out regional emergency information such as major meteorological disasters and missing children. As an integral part of the Integrated Public Alert and Warning System (IPAWS), the EAS plays a vital role in the publishing of public emergency information in the U.S.

 

The establishment of the national alert and warning system began in 1950s. The initially established Control of Electromagnetic Radiation (CONELRAD) was mainly used in the military field. Under military threats such as ballistic missile attacks, the designated AM stations would transmit relevant warnings on 640 or 1240 kHz. The CONELRAD was replaced by the Emergency Broadcasting System (EBS) in 1963. Since 1970s, the EBS was used to release non-federal emergency information including natural disasters, social security incidents and other emergencies, and it soon became a crucial channel for governments to broadcast civil emergency messages, warnings of severe weather hazards and other information. In 1976, the EBS began to use the Attention Signal, a combination of the sine waves of 853 and 960 Hz, to alert broadcasters to stand by for emergency messages. The Attention Signal is still used by the EAS. In the mid-1980s, the concept of Primary Entry Point (PEP) was proposed and the establishment of the EAS was in the making. In 1990, the Federal Emergency Management Agency (FEMA) set up the Primary Entry Point Advisory Committee to help manage the 34 PEP broadcast stations nationwide. In 1994, the Federal Communications Commission (FCC) organized the full establishment of the EAS. Up to 1997, the EAS had completely replaced the EBS, becoming a more comprehensive emergency broadcast system for public emergency information in the U.S.

 

I. EAS Basic Operating Mechanism

 

The nation’s highest governing body of the EAS is the Federal Emergency Management Agency (FEMA) under the Department of Homeland Security. The FEMA leads and directs EAS operations, EAS tests and simulation exercises at the national level, as well as funds projects on improving system operation. For instance, the Broadcast Station Protection Program (BSPP) supported by the FEMA once provided equipment such as emergency generators, remote camera equipment and electromagnetic pulse protection for more than 600 broadcasters participating in the national warning system program, so as to ensure that these stations could function properly and transmit timely emergency information in emergency. The FEMA assigns the FCC to manage broadcasters of the EAS and to make the technical standards, operational rules and procedures, and test plans of the system. It also coordinates with the National Oceanic and Atmospheric Administration (NOAA) to promote the implementation of the EAS program. Meanwhile, based on the updates of media technology and the actual operation of the EAS, the FCC will regularly seek advice for the summary and revision of the EAS operational rules from emergency management departments, broadcasters and other participating entities at state and local levels. State or local Emergency Communications Committees (SECC / LECC), consisting of government emergency management departments, broadcasters and other participating entities, are responsible for making the state and local EAS programs, as well as for organizing EAS-related trainings and seminars and coordinating the National Advisory Committees (NAC) to conduct relevant researches aimed at improving the spreading effect of emergency information. Moreover, the Media Security and Trust Committee, the Primary Entry Point Advisory Committee and other broadcaster associations and alliances also participate in the planning and management of some EAS work, supporting the continuous improvement of the system.

 

One of the requirements for the U.S. broadcasters to obtain the legal right to operate is to install the EAS equipment certified by the FCC. These entities include broadcast stations, television stations, cable and wireless television systems, Direct Broadcast System (DBS), Digital Television (DTV), Satellite Digital Audio Radio Service (SDARS), Digital Audio Broadcasting (DAB), cable video system etc. In the event of a national-level emergency, all broadcasters should send the presidential emergency alert notification via the EAS. Even if broadcasters’ application for not participating in the federal EAS program has been approved by the FCC, before performing their shutdown operation, they also need to relay the presidential notification when the federal government activates the EAS. At state and local levels, broadcasters can decide whether to join the local EAS programs.

 

At the national level, the EAS is activated by the U.S. President or the FEMA director authorized by the President. After sending the activation order, the President's Office sends notification to the FEMA Command Centers via the EAS special telephone line. On the one hand, the FEMA Command Centers send the presidential notification to the public through the National Public Broadcasting (NPR) network and the SirU.S.XM Radio Satellite Broadcasting Network. On the other hand, they transmit the notification to the EAS Primary Entry Point (PEP) through the EAS special telephone line, optical fiber, satellites and other transmission channels, then to Local Primary (LP) points through State Primary (SP) points, and finally to all other broadcast stations, television stations, cable network companies and other participating entities. In the hierarchical mode of information transmission, the presidential emergency alert notification can reach the people of the United States. The multi-level hierarchical chain of radio and television transmission, which starts from the PEP, is called the “Daisy Chain”. In the “Daisy Chain”, the responsibility of the PEP is generally borne by a group of local commercial broadcast stations designated by the FEMA. The initially established PEPs in the U.S. are mostly AM radio stations, and later FM radio stations are added. A State Primary (SP) entry point is a state relay station that monitors the PEP’s emergency alert signal. Each state in the U.S. basically has two state relay stations. A Local Primary (LP) entry point is responsible for monitoring and relaying emergency information from a State Primary (SP) entry point to other broadcast stations. At present, the United States is roughly divided into 550 EAS local operating areas, and each operating area usually has two Local Primary (LP) entry points.

 

The emergency information EAS receives is mainly from the President, the FEMA Director, emergency management departments at all levels, the Chiefs or the National Weather Service. Although the system has both manual and automatic function modes, most participating entities use the automatic transfer mode. In terms of emergency message relay, the President's Emergency Action Announcement (EAN) takes priority over any other messages. The national EAS activation must be prioritized over the state and local EAS ones.

 

In addition, local emergency message broadcasting is given priority over the state one. When the President issues emergency alert notification through the EAS, all broadcasters that receive the signals must relay the notification. For non-federal emergency information, the FCC regulates that it is broadcasters not state or local governments that determine whether to relay the information. At the same time, the EAS programs at state and local levels will take into account the disaster warnings issued by their meteorological departments, and the relevant parties would formulate the rules about in which categories and at what levels can warnings be send via the EAS.

 

EAS information transmission supports audio attachments, audio links and text-to-speech functions, and uses the SAME (Specific Area Message Encoding) protocol format. The information format consists of four parts: Preamble and EAS Header Codes (containing the identity of the information issuer, type of emergency, location, valid time); the Attention Signal; alert messages (audio, image or text); and Preamble and EAS End of Message (EOM) Codes. The FCC standardizes the code of the EAS information issuers and specifies codes of about 80 event types. The use of the code can accelerate the EAS identification and retransmission to broadcast (television) stations.

About Us Sitemap
(c) Copyright Emergency Management Office, the People's Government of Guangdong Province.
Facilitated by: Guangdong Provincial Department of Information Industry, Southcn.com (for Chinese version) and Newsgd.com (for English version)
All Rights Reserved.