User equipment, earthquake alert server and earthquake alert method thereof

An earthquake alert method for an earthquake alert server, the earthquake alert server comprising a network interface, a storage and a processor, the network interface connecting to a network, the storage storing a map therein, and the earthquake alert method being executed by the processor and comprising:

• (a) dividing the map into a plurality of geographic grids;
• (b) receiving an earthquake reporting message from each of a plurality of user equipments via the network interface, each of the earthquake reporting messages comprising a longitude and latitude value, a time stamp and an earthquake intensity;
• (c) mapping each of the earthquake reporting messages to one of the geographic grids according to the longitude and latitude value of the earthquake reporting message;
• (d) determining, for each of the geographic grids, a number of earthquake reporting messages of the geographic grid within a time interval according to the time stamp of each of the earthquake reporting messages corresponding to the geographic grid;
• (e) labeling the geographic grid, of which the number of earthquake reporting messages within the time interval is greater than a threshold, as a candidate earthquake geographic grid;
• (f) labeling each of the candidate earthquake geographic grids, which are adjacent, as an earthquake geographic grid;
• (g) determining, for each of the earthquake geographic grids, an earthquake reporting time of the earthquake geographic grid according to the time stamp of each of the earthquake reporting messages corresponding to the earthquake geographic grid;
• (h) choosing any two of the earthquake geographic grids to obtain a plurality of combinations that are non-repetitive;
• (i) dividing, for each of the combinations, the earthquake geographic grids into two groups according to a middle point of the two earthquake geographic grids of the combination in the map, and increasing a far value of the earthquake geographic grids in the group, including one of the two earthquake geographic grids of which the earthquake reporting time is later, by one unit;
• (j) labeling the earthquake geographic grid with the smallest far value as an epicenter grid;
• (k) determining an epicenter position, an epicenter occurrence time and an epicenter intensity according to the longitude and latitude value, the time stamp and the epicenter intensity of each of the earthquake reporting messages corresponding to the epicenter geographic grid;
• (l) generating an earthquake alert message carrying the epicenter position, the epicenter occurrence time and the epicenter intensity;
• and
• (m) transmitting the earthquake alert message to a plurality of remote devices via the network interface, wherein the remote devices include the user equipments.

A user equipment, comprising:

• a power source module;
• a transceiver;
• a motion sensor, being configured to sense a motion and generate a sensing signal;
• a positioning module;
• and
• a processor electrically connected to the power source module, the transceiver, the motion sensor and the positioning module, being configured to execute the following operations:
• determining that the user equipment is in a charging state in response to connection of the power source module to an external power source;
• determining that the user equipment is in a connected state in response to connection of the transceiver to a network;
• determining that the user equipment is in a stationary state in response to the sensing signal received from the motion sensor being smaller than a first threshold continuously within a preset time interval;
• activating an earthquake detection mode if the user equipment is being in the charging state, the connection state and the stationary state simultaneously to determine whether the sensing signal subsequently received from the motion sensor exceeds a second threshold;
• if the sensing signal subsequently received from the motion sensor exceeds the second threshold, then calculating an earthquake intensity, recording a time stamp and generating a longitude and latitude value via the positioning module according to the sensing signal;
• generating an earthquake reporting message comprising the longitude and latitude value, the time stamp and the earthquake intensity;
• and
• transmitting the earthquake reporting message to an earthquake alert server via the transceiver.