The Cayman Islands are located in a seismically active area, which means that earthquakes can and do occur.
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Grand Cayman lies close to the boundary zone of the Caribbean and North American tectonic plates. This transform boundary, where the plates slide past each other, is known to generate earthquakes.
Tsunamis are most often triggered by underwater earthquakes, with waves spreading outwards very rapidly from the site of the earthquake. Out at sea these waves typically measure around one foot in height and may travel at speeds of 400 mph. When the tsunami reaches the shallow waters of a continental shelf, the wave slows and its height increases.
Although tsunamis triggered by earthquakes can occur in Cayman, the probability is believed to be very low: Cayman’s underwater landscape, with steep drop-offs close to shore and very little continental shelf, may well reduce the risk of dangerous tsunamis.
Earthquake of January 28th 2020
Cayman experienced a magnitude 7.7 earthquake with its epicentre 67 miles from Cayman Brac, 154 miles from Grand Cayman and 84 miles North West of Montego Bay, Jamaica at 2.10pm on 28th January 2020. In addition to the Cayman Islands, affected countries included the Bahamas, Jamaica, Haiti, Honduras, and Cuba. Before this, the strongest recorded earthquake in the Cayman Islands, which occurred on 14 December 2004, measured 6.8 and very minimal damage occurred.
A tsunami threat warning was briefly issued and residents were advised to stay away from the coast. However within an hour, Hazard Management Cayman Islands announced the Tsunami All Clear, and although there were reports of multiple sinkholes and some reports of 1-2 ft waves, no major structural damage occurred.
In the aftermath of the initial quake, over 10 aftershocks were felt with the strongest tremor measuring 6.1 with the epicentre just 35 miles east of Grand Cayman.
Advance Preparation for Earthquakes and Tsunamis
Earthquakes strike without warning, and tsunamis with very little warning, so there is not a great deal one can do to prepare, but it is important to be familiar with the recommended course of action in case of such an event.
Cayman’s building code regulations ensure that modern buildings are strong enough to withstand a certain degree of quaking so the main hazards are unsecured appliances, objects and structures that could fall and cause injury, downed power lines and damaged water and sewerage systems.
As a preventative measure Hazard Management Cayman Islands recommends bolting down appliances and bookshelves, placing heavy objects on lower shelves and making sure one has emergency supplies – non-perishable food items, water, first aid kit, flashlight and a battery operated radio – at hand.
In the event of a tsunami, small buildings close to the coast are the ones at greatest risk as they are not designed to withstand the impact of a tsunami. For those living close to the sea, it is important to have a family emergency plan in place and to familiarize yourself with the nearest safe place to evacuate to.
What To Do During an Earthquake
If indoors: duck, cover and hold: get under a solid piece of furniture (e.g. a table or desk) or under a reinforced doorway, cover your head and eyes to protect yourself from flying objects, and hold on to the furniture with one hand. Do not move until the shaking has stopped.
If outdoors: remain outdoors until the shaking has stopped. Move to an open space away from buildings, glass, electrical cables or other objects that could fall and cause injury.
If driving: slow down and stop in an area free from hazards.
After an Earthquake
- Evacuate the building
- Do a head count and report any missing persons to emergency services
- Beware of broken glass and debris
- Be prepared for aftershocks which could cause further damage
- Check for fire, gas leaks, spilled chemicals, etc
- If at the coast, move inland in case of a tsunami
What To Do During a Tsunami
The Cayman Islands do not currently have a siren system (this is considered too costly to install and maintain), however as of 2018 phase 1 of a National Emergency Notification System was implemented which allows Government to interrupt radio broadcasts with emergency notifications.
There is usually very little warning time if a tsunami threatens so residents should NOT wait for an official warning but take action immediately. Below are some important tips for what to do in the event of a tsunami.
- If you are at the coast and see the water receding, move away immediately - this typically occurs just before the tsunami strikes
- Be aware that subsequent waves may strike at intervals of anywhere between 15 minutes and one hour
- If you are close to the coast and a tsunami warning is issued, move inland to higher ground or to a higher floor in a tall building
- If you are out at sea, stay out at sea