The earthquake-report.com opinion : NO and YES, … with the right use of the alert, many things can be done. Unfortunately, the vast majority of people are doing exactly the opposite of what they should do in such an event.
After every major earthquake there is hype for “earthquake early warning systems” like smartphone apps, computer tools, etc.
Let’s explain first what happens when an earthquake is triggered and probably explaining it, will give already part of the answer!
- Due to the extreme strength of 2 moving plates or sections of plates, the crust will rupture at the weakest point and an earthquake is generated. The rupture will lead to 2 main waves which will be disseminated from the rupture point or area.
a) the P-wave or Primary wave which is used by the alert systems to trigger the alert. Depending on the Magnitude and the composition of the ground layers the P wave generally travels somewhere between 4 to 8 km/second.
b) the S-wave travels approx. at 60% of the P-waves (let’s call it not so fast) and is responsible for the start of the shaking.
When a massive shallow earthquake hits below land, the shaking will be almost simultaneously felt together with the alert sound of an early warning app or tool, as there are usually only a few seconds in between both waves at short distances.
The area at risk for damage and injuries in 95% of the earthquakes is limited to tens of km, not to hundreds of km (with the exception of soft soil zones and large M7.5 events). Only national seismology agencies who have installed multiple instruments all over the country are able to trigger an alert. Measuring the alert and redistributing an alert signal will at least need some seconds. The area at risk is already shaking heavily at that time. Drop, Cover and Hold (the generally accepted preparedness standard) is the only recommended way to protect you from injuries. Further away from the epicenter (from 50 to several hundred km) the time in between the alert and the time the shaking starts can be used to take the Drop, Cover and Hold position or to follow the approved evacuation methods.
EAS can be of serious help in the case of Tsunamis and if the signal is triggered by National seismology agency. In most cases however, authorities have installed professional tsunami alert sirens along the coast.
The video below has been made by the Huffington Post, a USA on-line news website. Dr. Thomas Heaton directs the Earthquake Engineering Research Laboratory at CalTech who tells the audience that also the US is working on it, but some hurdles have to be taken. Please be aware that there is a short advertisement at the start.
The earthquake-report.com conclusion :
- early alert systems give a false feeling of security near the epicenter
- early alert signals should be provided by government or local authority specialized agencies
- early alert systems have to be used to take the Drop, Cover and Hold position until the shaking is over.
- early alert systems may never be used to evacuate buildings, unless the technology is there to invent alerts which can predict an exact time that the secondary wave would reach your location.
- early alert systems are being used and should be used even more in automatic “safety switches” like : trains (automatic stops), elevators (mandatory stop at next level blocking doors open), etc.
- early alert smartphone systems can be useful in smartphones when the Alert message is combined with your GPS location and if a voice can speak loudly “earthquake – weak shaking expected at your location”. All this without having to manipulate your phone!
- early alert systems can be beneficial in case of tsunami danger and for shutting down hospitals, lifelines or switching power supplies to retain essential services
- early alert systems DO NOT predict earthquakes
Early Warning Systems in Mexico City, Japan and cities where they are a long distance from the major fault zones but built on soft soils give useful data for citizens to prepare. However, other early alert systems should only be used for authorities.
We have found a very good article which was written in the Alaskajournal.com. The article describes what currently is tested in the USA and what an alert should have to do, how much time it allows etc.
Remarks based on our extensive experience following up what happens in real life during an earthquake :
- computers are normally not connected with backup power or batteries. We experience in 97% of all destructive earthquakes that power is lost within seconds
- smartphones are great BUT most Mobile network sending masts are NOT battery powered and will go off-line instantly when there is a power failure
- in case of battery powered masts (like in New Zealand) people are almost instantly run into an overheated network, disabling the great apps on your smartphone. A simple solution is repeated over an over again by earthquake-report.com. Block voice calls and send a Text message that “Due to an earthquake, only Text messages will be allowed until further notice”.