• PDF / 3,768,209 Bytes
• 110 Pages / 595.276 x 790.866 pts Page_size
• 5 Downloads / 201 Views

DOWNLOAD

REPORT

---

EARLY WARNING SYSTEMS Graham S. Leonard1, Chris E. Gregg2, David M. Johnston1 1 GNS Science, Massey University, Lower Hutt, New Zealand 2 East Tennessee State University, Johnson City, TN, USA

Synonyms Alerting system; Immediate warning system; Short fuse warning; Warning systems Definition The term early warning system often refers to the technological monitoring, telemetry, and notification aspects of warning systems. The term is also used to distinguish cases where a warning is able to be delivered in a time frame that permits protective action, such as may occur for tsunamis, volcanic eruptions, or severe weather, but not necessarily an earthquake. Overview Synonyms While all aspects of a warning system are sometimes referred to as an early warning system, the term early warning system overlaps most in meaning with immediate and short-fuse warning systems which are warning systems designed in regard to hazardous events with very short durations of time between the onset of the event and the occurrence of a hazardous process. Monitoring Methods used for monitoring natural hazards vary widely, but usually revolve around one or more environmental sensors that telemeter data to communications hardware, which is capable of disseminating a warning notification.

Sensors detect a variety of geological and geophysical phenomena, including, but not limited to pressure, temperature, distance, chemistry, electromagnetic radiation, and ground-shaking. Monitoring equipment is often located in remote areas, requiring special design or housing to withstand extreme environmental conditions of cold, heat, and precipitation, in addition to its own power supply, which would include batteries and solar or fuel generators. Monitoring equipment may be positioned in permanent to semipermanent fixed locations or mounted on vehicles, balloons, aircraft, or satellites and positioned in multiple areas over short time periods. Some monitoring networks are permanent, whereas others are deployed in response to initial signs of unrest.

Telemetry Monitoring equipment is sometimes located far from population centers. This requires development of a telemetering network that can provide communications links between the monitoring equipment and scientists or emergency managers. Data are often telemetered over a fixed communication network (e.g., a phone line) or wireless (e.g., mobile phone, VHF-UHF radio, satellite uplink) technology. Regular testing is needed for networks that are not routinely used. Automated decision-making Warning systems need to allow for a decision to notify (or not) based upon predetermined thresholds of monitoring data provided by the monitoring equipment. For early warning systems built around hazards with short lead times, this decision is often made automatically, or at least the system automatically processes monitoring information and provides a few simple options to a decision-maker. Warning thresholds for monitored data need to be preplanned for such a decision to be made automatically or made quickly when revie