Does it take a while to average data from different sensors or is there another reason?
For example, I saw an earthquake today that was a 4.3 one minute after it happened then was downgraded to a 4.1 only 15 minutes later
In: Planetary Science
The amount of energy in a earthquake that reach a sensor depend on the distance from the earthquake. It both the location and the depth of the earthquake that matters. You determine location by diffrence in arrival time to different sensors.
The P waves travel at a speed of about 6 km (3.7 miles) per second at then surface. So after 1 minute the wave have only traveled 360 km. Sensors need to be even closer to be included because it take time to calculate and distribute the information. After 15 minutes information from more sensors can be included and analysed so a correct value can be presented.
The S waves that do more damage on the surface tralve at only 3.4km (2.1 miles) mes second.
Because of the travel time warning can be sent to location farther away from the earthquakes. What action are take depends on the magneude it will have when it reach the location. It will be safer to send what is a high magnetude from the data that has been analyses instead of to low a value.
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