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Comparison between the 2007 Cyclone Gonu Storm Surge and
the 2004 Indian Ocean Tsunami in Oman and Hormozgan, Iran
Hermann M. Fritz*
School of Civil and Environmental Engineering, Georgia Institute of Technology, 790 Atlantic Drive, Atlanta, GA 30332, USA
Abdolmajid Naderi Beni
Iranian National Institute for Oceanography and Atmospheric Science, Tehran, Iran
Abstract: Super Cyclone Gonu was the strongest tropical cyclone on record in the Arabian Sea. Gonu attained
Category 5 status with peak 1-min sustained winds of 263 km/h with gusts up to 315 km/h and a central pressure of 909
mbar on 4 June 2007 about 475 km east of Masirah Island off the coast of Oman. Cyclone gradually weakened due to
cooler water temperatures and drier air as it approached the Arabian Peninsula. Cyclone Gonu crossed the eastern-most
tip of Oman at Ras al-Hadd with winds of 164 km/h late on 5 June, making it the strongest tropical cyclone on record to
strike the Arabian Peninsula. On 6 June, the cyclone turned to the north-northwest and made landfall on the Makran
coast of Iran as a tropical storm on 7 June. Gonu caused about $4 billion in damage and at least 49 deaths in the Sultanate
of Oman, where the cyclone was considered the worst natural disaster in its history. Gonu dropped heavy rainfall near
the eastern coastline, reaching up to 610 mm, which caused wadi flooding and heavy damage. The shore parallel cyclone
track resulted in coastal damage due to storm surge and storm wave impact along a 300 km stretch of Omani coastline.
In Iran, the cyclone caused 23 deaths and $215 million in damage. The widespread failure of tide gauges along the Gulf
of Oman called upon a field survey crew to collect high water marks based on established protocol. The team surveyed
270 km of impacted Omani coastline from Ras al-Hadd to Abu-Abali within 2 months of Gonu’s landfall from 1 to 4
August 2007 (Fritz et al., 2010). The team measured coastal high water marks, inundation distances, wadi and overland
flow depths. Further coastal erosion and deposition was documented. Ephemeral infrastructure damage was recorded at
various scales. The high water marks peaked at Ras al-Hadd at the eastern tip of Oman exceeding 5 meters. The steep
bathymetry between Ras al-Hadd to Muscat limited the relative contribution of storm surge, but increased storm wave
impact. Some 500 km of Iranian coastline from the Strait of Hormuz with Qeshm and Hormuz Islands to 150 km east of
Jask were surveyed from 10 to 17 October 2010, while part of a UNESCO field workshop searching for evidence of
Makran tsunamis. Cyclone Gonu high water marks exceeded 5 m at several locations along a 100 km stretch of coastline
extending east of Jask to Vanak. Cyclone Gonu’s storm surge and storm waves were observed up to 80 km north of Ras
al-Kuh inside the Strait of Hormuz. The field survey in Hormozgan also documented the October 1981 storm impact and
coastal inundation on Hormuz Island. The 1981 storm caused at least 200 fatalities mostly at sea in the Strait of Hormuz.
A high resolution finite element mesh of the Arabian Sea is created to model the storm surge of Gonu using the
Advanced Circulation Model (ADCIRC). Modeling results are compared to measurements and used to determine the
contribution from storm surge and storm waves. The storm surge flooding hazard is expected to increase in the rare
event of a cyclone landfall along the shallow shelf between Muscat, Oman and Al Fujayrah, United Arab Emirates
(UAE) or near the Island of Masirah, Oman. Prior to Super Cyclone Gonu in 2007, only two similar cyclones struck the
coast of the Sultanate of Oman in the last 1200 years. The two storms (in 1890 and 865) entered the Gulf of Oman, like
Gonu, except both turned southwest to strike the northern coast of Oman. The 1890 storm drenched the coast from Soor
to Suwayq and caused flooding inland as far as the Wadi Samail and Wadi Beni Ghafir. Matrah and Muscat were the
hardest hit with many ships washing ashore. The storm is known to have killed about 727 people and destroyed date
trees equivalent to $1.5 billion at the time. While less is known about the 865 storm, it had similar effects as the 1890
storm between Gobrah and Sohar. The multi-hazard aspect is analyzed by comparing overlapping field observations of
Cyclone Gonu with the Indian Ocean Tsunami of 2004 in Oman and Iran. Corresponding 2004 Indian Ocean tsunami
heights inside the Gulf of Oman were recorded based on eyewitness accounts while surveying cyclone Gonu in Oman in
2007 and Iran in 2010. Oman’s Arabian Sea coastline from Masirah Island to Salalah was surveyed in 2005 (Okal et al.,
2006). The 2004 Indian Ocean tsunami may represent a worst case far field tsunami hazard scenario for areas inside the
Arabian Sea. The 2004 Indian Ocean tsunami exceeded the 2013 Baluchistan (Pakistan) tsunami in the Arabian Sea. The
1945 Makran tsunami remains the largest documented tsunami in the northern Arabian Sea (Okal et al., 2015). Coastal
protection in the West Indian Ocean must be approached from a multi-hazard perspective given the combined tropical
cyclone and tsunami hazards. The importance of raising tropical cyclone and tsunami public awareness is highlighted.
* Corresponding author. Email: fritz@gatech.edu
Fifth International Conference on Estuaries and
Coasts (ICEC2015), November 2-4, 2015,
Muscat, Oman
ISSN: XYZ
Key words: Tropical Cyclone, Storm Surge, Gonu, Tsunami, Indian Ocean, Arabian Sea, Gulf of Oman, Strait
of Hormuz, Makran
