Wagwater Earthquake Zone Understanding: The Motivation
This is the formal beginning of a documented series of posts (reports), relating to my field work, geared primarily towards understanding better, Jamaica’s Active Wagwater Earthquake Zone. The reveal of content herein, should have applicability in a number of areas of benefit to Jamaica, (non-exhaustive):
- Disaster Management (earthquake, landslide).
- Construction longevity (Homes/Communities, Roads).
- Agriculture (Farming, Lumber).
- Tourism.
Relevance of This Report
The active Wagwater Earthquake Zone has produced at least one Moderate Earthquake (Mg 5+) since 2024. Before this, the 1993, Mg 5+ earthquake also had an epicenter within the Wagwater Earthquake Zone (one in 23 yr recurrence period). And after this, 2 Earthquakes with a Magnitude of 4+ have occurred in 2025 & 2026 respectively.
With sections of the population-dense St. Andrew residing within this zone (potentially 100,000 residents, minimum), our knowledge on the active geology of this zone; as well as the applicable engineering, land use and building codes (policy, plans, enforcement), can help mitigate significant losses (economically & otherwise), for our & future generations.
Peters Rock-Lindos Gap: Geology Observations
Earthquake Trend & Displacement
Generally, the geology is deformed in 3 directions: NW/SE, NE/SW, WSW-ENE. Because of this, the rocks display zones of significant weathering, erosion, and in some locations (Woodford & Peters Rock) relatively large jointing (1-8 inches diameter), along slip planes (parts of which hang over main road–hazard to motoring public). Predominant displacement was also observed generally along the WSW/ENE trend. Landslides were observed with lithology highlighting this orientation, generally throughout the area.
Lithology
Deeply weathered volcanics, at Peters Rock. Notice the impermeable nature (clays).
Felsic-Intermediate Volcanics at Peters Rock.
Deeply Weathered Volcanic, responsible for silty-clay soil, at Peters Rock and other locales within study area.
Cooked Carbonate (Marble) at Woodford.
Cooked Carbonate (Marble) at Woodford.
Close up: Marble-Clast, Blueschist at Maryland.
Slab breakage: Cooked Carbonate (Marble), with ghost sedimentary structures–low temperature and/or pressure formation conditions. At Woodford
Close up: Blueschist with Marble-Clast; and Olivine-Basalt
Andesite-Basalt at Maryland: breaks down to clays.
Highly fractured Carbonate at Lindos Gap
Highly fractured Carbonate at Lindos Gap.
General Geology Cross-Section with Infererred Faults (Peters Rock- Lindos Gap); NW/SE transect.
Landforms & Environment
Hope River, captured at Lindos Gap.
Hope River Flood Plain, and N/S Fault Scarp. Captured at Lindos Gap.
Settlement: Hope River Flood Plain, with N/S Fault Scarp; captured at Lindos Gap.
Cliff face bounding Kintyre, cut by WSW/ENE Fault.
Overlooking Cliff face bounding Kintyre
Overlooking Maryland Valley from Woodford Sq.
Overlooking Hollywell (section of Blue Mountains-partially covered by low clouds) from Woodford Sq.
Mineralization Observations-Iron Skarn
At Maryland
At Peters Rock
Cross-section highlighting general lithology, earthquake trend & Iron-Skarn Mineralization trend (general).
Engineering-Geology Related Insights
Three earthquake trends were generally observed throughout the transect. Similarly, these trend patterns were observed at all exposed landslides (fresh) locations.
Watch Related
High Risk for Road Block & Breakaway: sections of Maryland Thoroughfare & Woodford Entrance
Given the active nature of all 3 earthquake trends; estimated average annual movement rate (2mm); coupled with the highly fractured, weathered & in some locations, jointed lithologies, all roads within this area are vulnerable to road blocks.
To mention one: The Marble overhanging and dipping to the narrow (single lane) road, should be meshed at the least.
Safe Housing Longevity Insights
With estimated annual movement of the the Wagwater Earthquake Zone averaging 1-2mm, relative to the more active slip area of the Plantain Garden Fault zone (averaging 7-9mm), it can be interpreted that the Wagwater fault zone is an area of stress-building. Therefore, near future (minimum one in 20-30yr), dip-slip & oblique-slip earthquakes of moderate magnitude (minimum), is a likely occurrence. And with it, further land deformation (landslides, erosion, weakened foundations), can occur. Hence, housing interests must implement through policy (building code design; land use zones) & enforcement, the strongest measures to mitigate losses…