"Even if it’s in the middle of the night, the team leaders are woken up to deal with the emergency. There’s a tremendous amount of responsibility resting on our shoulders."
By ILANA SHTOTLAND THE GEOLOGICAL Survey in action detecting earthquakes.(photo credit: David Weil/Anaba Photo)
Six months after beginning his position as director of the Geological Survey of Israel, Prof. Zohar Gvirtzman was forced to deal with an extremely challenging situation, as Israel recently experienced two earthquakes in the North just 10 hours apart from each other.
“The activity we’ve experienced of late has been abnormal in that a section of the Syrian-African Rift Valley that stretches from Beit She’an and eastward into Jordan, which has been relatively quiet for decades, has experienced dozens of quakes,” Gvirtzman explains. “Just three weeks ago, for example, within a 24-hour period, we recorded over 30 earthquakes, two of which could be felt.”
Why has this been happening?
“This is an active area, but there has been an especially large amount of activity there over the last few weeks. It’s difficult for us to specify the exact reason behind these changes.
“It could be that there’s a huge crack in the earth’s crust that sometimes breaks open and initiates an earthquake along the crack, but why this would take place right here, at this specific time, yesterday in a different location, and tomorrow in a third place, well we don’t always have a precise answer to these questions.
“I can’t give you an accurate reason why the earthquake took place in the Beit She’an region.”
‘WE MEASURE the seismic magnitude of the quake.’ (credit: COURTESY GEOLOGICAL SURVEY OF ISRAEL)Do the earthquakes that recently shook that region worry you?
“Yes, we and all the other organizations that track earthquake data are quite concerned, especially since we have not been able to discern why this is happening. We have personnel on duty 24/7, and if we pick up signals that signify possibly dangerous outcomes, then the duty officer notifies his manager, and so forth up the hierarchy, just like a doctor in a hospital would call her superior who is on call at home.
“Even if it’s in the middle of the night, the team leaders are woken up to deal with the emergency. That’s exactly what happened a few weeks ago, when we gathered the whole team at 9 p.m. and then again the next morning at 5:20 a.m. There’s a tremendous amount of responsibility resting on our shoulders.”
Do you think the recent earthquakes are a precursor for an even stronger earthquake in the near future?
“We in the science community still do not have the capability to predict when an earthquake is going to take place. What we do know is where it will take place, since earthquakes only occur within the tectonic plates located in the earth’s outer crust. So, for example, because neither Jerusalem nor Tel Aviv is located along the Syrian African Rift, we don’t expect either of these cities to be hit hard by an earthquake.
“We rely on statistical data to predict how often an earthquake will occur. We measure the seismic magnitude of the quake, which can reach up to 5, 6 or even 7 on the Richter Scale. We can predict the amount of time between each eruption, the magnitude, the location, but not precisely. Our data shows that an earthquake with a magnitude of 6 on the Richter Scale takes place every 100 years on average. But in reality, it could happen every 50 years or 150 years.”
Where are we now in this cycle?
“Not in a good place at all, since the last big earthquake in Israel took place in 1927, so we’re coming up on 100 years very soon. But it’s also possible that there’ll be a break of 150 years, or perhaps even 200 years, between the last one and the next one.
A number of organizational changes have been implemented at the Geological Survey of Israel since Gvirtzman was appointed director.
“Two years ago, the Seismology Department at the Geophysical Institution in Lod was transferred to the Geological Survey in Jerusalem, and the department continues to carry out the seismology work at its new home,” Gvirtzman continues. “In addition, we’ve just finished putting the last touches on our revolutionary TRUAA Early Warning System, which we developed to sound an alarm when an earthquake is imminent. We are pleased to announce that the system has been connected to Israel’s Home Front Command alarm system.
“We are responsible for giving the signal, and the Home Front Command is responsible for sounding the alarm. Our office began working on this system 15 years ago, and our goal was to have it up and running by this past March. It was quite exciting that we were able to reach the finish line ahead of schedule. It is incredible to see that all this work has come to fruition after so many years of feeling like it was just a dream.”
‘WE MEASURE the seismic magnitude of the quake.’ (credit: COURTESY GEOLOGICAL SURVEY OF ISRAEL)How does the TRUAA Early Warning System work?
“Because we’re not able to accurately predict when an earthquake will take place, we can’t send out a warning until the earthquake is already happening. For example, if an earthquake starts in the Jericho/Dead Sea area, the waves quickly begin to spread out. It could take, say 10 seconds to reach Jerusalem, or 30 seconds to reach Tel Aviv. Our system’s sensors take five to seven seconds to register and process the data, at which time they send out warning signals to surrounding areas that could be affected.
“Until now, the Home Front Command sirens have only been used to set off sirens that warn residents of missile attacks on Israeli population centers. From now on, there will also be sirens warning of earthquakes. Our system detects the earthquake and transmits a signal to the Home Front Command, which then will activate the sirens, as well send out a notification on its app.”
Does the earthquake have to be a certain strength to sound an alarm?
“Yes, the sirens would only be activated in the relevant locales for an earthquake that measures at least 4.5 on the Richter Scale. If our system identifies an earthquake of 6 or above, it will sound alarms throughout the entire country. The extremely complex algorithm on which our system is based was formulated at the University of California, Berkeley, and we’ve worked closely with a team there to adapt it so that it perfectly fits Israel’s needs. It has two control centers – one in Jerusalem and one in Lod.
“We are very proud and honored to join the ranks of other developed countries around the world that have access to such sophisticated technology.”
The news about the warning system is wonderful, Gvirtzman explains, “except we are still waiting to see if the State of Israel is willing to allocate the necessary funding for long-term maintenance and further research and development.
“It was not possible to estimate future maintenance costs at the start of this project, since Israel is one of the few countries around the globe that has implemented such a sophisticated earthquake warning system.”
How high do you expect maintenance fees to be?
“A few million shekels, which is just a drop in the bucket compared with the billions of shekels Israel is spending on earthquake preparedness. But for our research institution, which employs 120 people in long-term positions, plus another 40 ad-hoc positions, this money is crucial for our activity.
“We are currently in the process of applying for the relevant government grants, and I hope all of the funding requests will be approved in the near future.”
What can be done in the meantime?
“Instead of wasting time wondering if the next big earthquake will take place in five years or tomorrow, we need to make sure that all new residential buildings follow strict guidelines that will protect them from earthquakes. This way, when the next big earthquake comes, we’ll have many fewer casualties.
“These guidelines have been in place since 1975, which means that any structure built before that time should be reinforced, and the government is working diligently to make sure this happens.”
Do you worry that Israel will not fare well when the next earthquake will hit us?
“I’ve been actively working in this field for many years now, and I am quite concerned about all of the older structures that have not been reinforced. We’re talking about a huge percentage of the population. I think the government needs to take a more proactive role in strengthening these buildings. Some of them really should just be demolished and rebuilt.
“This is the most important task we should be taking care of now before it’s too late.”
