Photo: IDF

Is Israel vulnerable to earthquakes?

By 4 PM today local time, there had already been 135 earthquakes worldwide according to the European Mediterranean Seismological Center.

The last earthquake to occur in Israel was an M3.3 in the Galilee on 8 November.

It is important to keep in mind that seismic activity constantly occurs around the globe on a daily basis, recorded by sensitive seismometers to record the time, location and intensity of quakes in whole numbers or decimal fractions.

The Director of Israel’s Inter-Ministerial Steering Committee for Earthquake Preparedness, Amir Yahav, told TV7 that they are so “commonplace” that “tens of thousands” are felt globally each year, but he emphasized that the vast majority are “weak in intensity and do not cause any damage.”

As an overview, anything registering below an M6.0 is unlikely to inflict more than slight damage to structures built in compliance with established building codes; while 3.5 – 5.4 are often felt but rarely result in damage, and 3.5-1.0 or less are generally not felt by inhabitants even though they are recorded.

Following are the basic earthquake categories:

Micro <1.0 – 2.0

Minor 2.0 – 4.0

Light 4.0-5.0

Moderate 5.0 – 6.0

Strong 6.0 – 7.0

Serious 7.0 – 8.0, capable of major destruction

Great 8.0 – >9.0, with damage spanning 100s of kilometers.

Dr. Amos Salamon, who is a Senior Researcher at the Geological Hazards Division of the Geological Survey of Israel (GSI), told that while minor quakes are not infrequent, “destructive events” that cause damage only occur in Israel every 60-100 years. Both of the last minor surges in Israel occurred in the Galilee region in 2018 and 2013.

The strongest of today’s earthquakes (at the time of this printing) was a 4.4 magnitude (M4.4) in the Banda Sea. There were several 4.3M quakes at locations ranging from Halmahera, Indonesia and Antofagasta, Chile to Guerrero, Mexico and Salta, Argentina. There were also two separate M4.2 earthquakes in Northern Colombia; as well as an M4.2 in Papua, Indonesia and an M4.0 near the northern the Papua coast.

Other notable recent quakes were an M4.1 that hit Syria at 1:47 PM yesterday afternoon, an M4.1 in the Lebanon-Syria region at 10:08 PM on 26 November, while 3 separate quakes rattled Turkey that same day registering M2.5, M2.4 and M2.2.

Turkey is still recovering from its deadliest quake in nearly a decade. 115 people died in the western city of Izmir, mostly in 17 damaged or collapsed buildings, when an M7.0 struck the Aegean Sea on 30 October; also killing 2 on the Greek island of Samos.

Turkey is crossed by fault lines and is prone to earthquakes. More than 500 people were killed in a 2011 quake in the eastern city of Van, while another in January this year killed 41 people in the eastern province of Elazig.

It was actually two powerful quakes in northwestern Turkey that killed 18,000 people in 1999 that prompted the Israeli government to establish the appointed the Inter-Ministerial Steering Committee for Earthquake Preparedness in August of the same year. According to its official website, the destruction in neighboring Turkey “once again illustrated each country’s vulnerability to the enormous destruction.”

Mr. Yahav said that earthquakes nevertheless remain such a “great concern in Israel” that “according to government resolutions it is the second most dangerous scenario (after war scenario).”

Advanced nations such as Israel are unwilling to take risks associated with what can be devastating effects of earthquakes and devote tremendous resources to research and scientific monitoring of seismic activity.

Strict building codes are also enforced in these countries, often based on policies set in Europe or the United States, to design infrastructure and other structures able to withstand the tremors. It logically follows that less modern states or rural areas that fail to adhere to such guidelines are more vulnerable to damage.

The Committee consists of 40 representatives of government ministries including the Home Front Command, emergency bodies, research institutes and civic organizations. Focus is on the prevention of disaster by improving construction and infrastructure to withstand shocks, including the initiation and funding of development and updating of building standards, studies dealing with the development of construction methods with high earthquake resistance, and formulation of a budgeted government plan for the reinforcement of existing residential and public buildings housed by government ministries.

“An earthquake in San Francisco would cause far less damage than one of the same magnitude in Istanbul or Cairo,” Dr. Salamon told TV7.

Authorities can also undertake precautionary measures during and immediately after the event to minimize damage and facilitate greater recovery. According to the Director of the Steering Committee, the Israeli government has ordered preparation for the care of “7,000 casualties, 8,600 badly wounded, 37,000 lightly wounded, 170,000 homeless, 28,000 destroyed/heavily damaged buildings, 290,000 medium to light damaged buildings.”

The basis of such great concern, Mr. Yahav explained, is due to the construction of some 80,000 buildings prior to the enactment of the national earthquake building code in 1980. Even though “all critical infrastructures have programs of earthquake preparedness.. it is not enough,” he said, citing the 2018 State Comptroller report.

“Earthquakes or tsunami can occur any given time in our region,” Mr. Yahav went on to stress, underscoring that, “Preparedness, exercising possible scenarios and making rehabilitation plans are key elements for saving lives of thousands of people.”

Earthquakes are one of the causes of tsunamis, in addition to volcanic eruptions or other major underwater disturbances such as detonations or meteors. The displacement of a large volume of water in oceans or seas can be devastating, as witnessed in the 26 December 2004 earthquake and tsunami in the Indian Ocean.

As a scientist, Dr. Salamon’s interests are earthquake hazard evaluation, tsunami, historical earthquakes in the Levant and seismotectonics of the Eastern Mediterranean. His main projects and grants relate to Tsunami inundation hazard maps for Israel and Tsunami early warning.

When asked about the likelihood of tsunamis, Dr. Salamon told TV7 that “yes, of course Israel is at risk, but not as high as that of Japan.”

When will the next major earthquake hit Israel? Historical data indicates that a strong earthquake will occur even though its timing and intensity are nearly impossible to predict. Mr. Yahav said that research reveals energy accumulation capable of potentially producing a “massive 7-7.5 magnitude earthquake” in some areas along the Dead Sea Fault in which “we estimate that all countries in the region will be afflicted.”

In geological terms, Israel is situated on what is known as the Sinai Sub-Plate– which shifts at the relatively slow rate of about half-centimeter each year. Very simply, an earthquake can result from the ensuing friction and stress create seismic waves along those fault lines. The severity of an ensuing quake is determined by the relative speed of such motion. Earthquakes are focused on the contact between these plates – which is called the Dead Sea Rift valley, or the Syrian-African Fault line in popular terms.

In contrast, the rate of relative motion along the North Anatolian Fault – which is a long plate border in Turkey that crosses nearby Istanbul, is 5 times higher than that of the Dead Sea Fault between Israel and Jordan. Indeed, Turkey suffers many more destructive earthquakes that the Levantine region.

Cyprus also shifts some 2 centimeters per year, at a rate 3-4 times higher than Israel.

“Global experience shows that citizens’ proper preparation for an earthquake and behaving according to the defensive guidelines during an earthquake, have saved many lives,” stresses Israel’s Steering Committee website.  There is also vocational training with government agencies, emergency and civilian groups toward the improvement of preventive deployment programs and the response capabilities; including “the fields of engineering, rescue, population needs assessment, international assistance, information, and study missions to earthquake sites around the world.”

Toward that end, advisories in Hebrew, Arabic and English are regularly issued to the general public by the Committee for the Production of Public Information and the Execution of Public Information on television, radio, the internet and other materials disseminated in cooperation with local authorities.

— By Erin Viner