The Earthquake Hazard Expected In Lebanon

10080-CVLE231-Engineering GeologyInstructors: Lina Ahmad Jaber

By : Mohammad Saeed Khawwam 201401379

Report

Seismic Hazard of Lebanon

• Reliable historical records, observational data and field information show that Lebanon is in an active region, where high magnitude earthquakes and tsunamis have struck and destroyed Beirut several times in the past, causing severe destruction and high death tolls.

• Energy release associated with rapid

movement on active faults is the cause of most earthquakes

a full account of the most damaging historical earthquakes in Lebanon is given.• 1063 Aug- An earthquake caused the walls of Tripoli to fall down, and there was widespread destruction

in Antioch, Laodicea ,Tyre, Acre and in many other cities in both Byzantine and Arab territory.• 1202 May 20- An earthquake occurred in the Middle East around daybreak. Tyre and nearby Baalbek

were mostly affected; not to mention rock falls in Mountain Lebanon that killed 200 people.• 1354 Oct 28 - An earthquake shook Baalbek causing many casualties.• 1759 Oct 30 - An earthquake totally ruined Safad and Qunaitra. The Damage extended to Saida, where a

few houses collapsed. In addition to that, a tsunami flooded Acre and the docks at Tripoli.• 1759 Nov 25 -This was a major shock which lasted 50 sec. and almost totally destroyed all villages in a

narrow zone extending to the north-east for about 120 km along the Litani and Bekaa Valley into the upper reaches of the Orontes river in southwest Syria.

• 1837 Jan 1- An earthquake occurred at about four in the afternoon and lasted about 20 seconds. It was probably a multiple event, the second shock occurring about five minutes after the main shock1956 Mar 16- An earthquake shook the southwestern Lebanon range. In all, 122 people were killed in 33 settlements and villages. The shock triggered slides, rock-falls and damaged retaining walls of mountain roads

• Based on the chart above, the maximum return period of an earthquake with a magnitude higher than 7.0 , since the year 1000 A.D was 139 years

• Such an earthquake struck the Lebanese region in 1837, i.e. 175 years ago. This puts the country in the critical time period.

• The presence of the newly discovered Mount Lebanon thrust does indeed have a significant impact on the earlier established seismic hazard map of Lebanon, especially for the coastal area where more than 70% of the country’s population and capital investments concentrate.

The proposed seismic zone parameter for the coastal area between Saida and Tripoli.• Based on the results of a study published by “Lebanese Science Journal, Vol. 12, No. 2, 2011”, the following

conclusions can be drawn: “Lebanon is a country of moderate to high seismic hazard. The expected with a 10% probability of

exceedance in 50 years

The hazard Of Earthquake :This increase in seismic hazard implies that all civil engineering facilities, including buildings and bridges, that are yet to be constructed in the coastal zone between Saida and Tripoli should be designed using the design and reinforcement detailing requirements (in reinforced concrete structures) of “high seismic hazard” established in international codes of practice.”