As Submitted to the Caribbean Journal of Science for Review, 4 March 2002

As submitted to the Caribbean Journal of Science for review, 4 March 2002.

Late Quaternary Eruption Forecasting

Of The Lesser Antilles Arc Volcanoes

ROBERT B. TROMBLEY[1], Principal Research Volcanologist, Southwest Volcano Research Centre, Apache Junction, Arizona 85219-9169 USA

The history of the Lesser Antilles volcanoes covers a long, progressive development along with the history of the Caribbean area. The Lesser Antilles, which separate the Caribbean from the Atlantic, generally form an arc that begins in Saba in the north and extends to Grenada in the south almost to the coast of South America (see Figure 1 below, Donovan, 1994). Included in the arc are St. Kitts, Nevis, Montserrat, Guadeloupe, Dominica, Martinique, St. Lucia, St. Vincent and Grenada. All of the islands have been built up from the floor of the sea by volcanic action, a process that is continuing. A few miles north of Grenada, there is a submarine volcano named Kick-‘em-Jenny, the only known live submarine volcano in the Lesser Antilles. This volcano has erupted at least ten times since 1939, on one occasion sending a column of smoke and ash 900 feet (274 meters)into the air. During the 1962 eruption, the probable centre of Kick-‘em-Kenny’s eruption was 762 feet (232 meters)underwater. In 1966, the volcano had risen 132 feet (40 meters)closer to the surface, and when sounding were taken in 1978 it had grown another 105 feet (32 meters). At its present rate of growth, Kick-‘em-Jenny may very well break the surface and emerge as a volcanic island early in the 21st century.

Figure 1. The volcanoes of the

Lesser Antilles.

Many of the volcanoes of the Lesser Antilles are currently inactive, their tops beneath the sea and deeply buried under the coral debris of the Caribbean. But 17 of those volcanoes are classified as still live, and of these, and counting submarine volcano Kick-em-Jenny, ten have erupted in historic times.

The Lesser Antilles is an island archipelago. The islands are built primarily by volcanism above a subduction zone. The mechanism involves the subduction of the Atlantic Ocean seafloor westward beneath the Caribbean tectonic plate at an annual rate of approximately 20mm yr-1 (Sigurdson & Carey, 1991). When compared globally to other island archipelagos about the globe, the Lesser Antilles are relatively short, long-lived, since the Eocene epoch, of only moderate vigour and exhibits a very well developed accretionary wedge in the southern portion of the archipelago. The true chain of islands that make up the Lesser Antilles extend in an 528mile (850 Km) long arc that extends from Sombrero in the northern portion of the chain to Grenada south. The Lesser Antilles are separated from the Greater Antilles by the Anegada Passage and the Venezuela continental margin, which starts just south of Grenada (Case, 1975).

Forecasting the time, place, and character of a volcanic eruption is one of the major goals of volcanology. It is also one of the most challenging goals to achieve. The current goal in forecasting volcanic eruptions of the Lesser Antilles, and the precept of this paper, is to provide the best possible forecasts. This is based on the geologic history of the volcanoes under study as well as the day-to-day vital signs of the volcanoes in terms of surface deformation, micro-earthquakes, temperature, gas emissions, tilt, and other measurements of the live Lesser Antilles volcanoes. Our investigations have shown that there is also a difference in the eruption patterns of volcanoes from Martinique traversing northward on the arc and volcanoes traversing southward from Martinique. This paper shall present the finding and possible implications, relative to forecasting future eruptions, from this data.

The software package, ERUPTIONPro 10.3, as developed by this writer, (Trombley, 1996) performs a statistical analysis on loaded volcano eruption data from both historical and current real-time or near real-time data. It produces three forecasts; a statistically projected next eruption year, the next forecasted beginning eruption year with a 50% probability of eruption occurrence, and finally, the next forecasted beginning eruption year with a 95% probability of eruption occurrence. To date, the analysis for the years 1998 through 2002 (to date) have been completed. ERUPTIONPro 10.3 has been most favourable in its analysis capability, rendering an accuracy better than 90% since the incorporation of newer, improved algorithms beginning in late 1997. A complete paper and detailed discussion of ERUPTIONPro 10.3 (Trombley & Toutain, 2002) can be downloaded from the following Internet URL address: then select the article entitled “Eruption Pro 10.3 – The New & Improved Long-Range Eruption Forecasting Software”.

The following presents a brief summary of those 17 volcanoes. There are seventeen numbered volcanoes as listed in the “Volcanoes of the World”, 2nd Edition by T. Simkin & L. Siebert (1994). They are, in order of listing, Saba, The Quill, Liamuiga, Nevis Peak, Soufriere Hills, La Soufrière (Guadalupe), (Unamed), Morne au Diable, Morne Diablotins, Microtin & Morne Trois Pitons, Morne Patates, Montagne. Pelée,Hodder’s Volcano (Not a volcano), Qualibou, Soufriere (St. Vincent), Kick-‘em-Jenny, and St. Catherine.

A Brief description of each volcano listing name, latitude, longitude, elevation, historical eruption characteristics (see Table 1a – 1k) of each eruption & Catalogue of Live Volcanoes Number, is as follows:

Saba17.63N63.23W 887m1600-0

Volcano Saba, is a stratovolcano with a single historic eruption shortly before 1636 AD. The only historic eruption was from a flank vent on the south-west side and produced pyroclastic flows. It is a Dutch island and marks the northern most limit of the Lesser Antilles.

Table 1a. SABA

The Quill17.48N62.95W 601m1600-02

The Quill is a stratovolcano that forms part of St. Eustatius Island. The Quill has had three Holocene eruptions. Using the carbon-14 dating method, eruptions have been dated at 5990 and 5860 BC and 400 AD. The 5990 BC eruption was Plinian in style. All eruptions were from the central vent and produced pyroclastic flows.

Table 1b. THE QUILL

Liamuiga17.37N62.80W1,156m1600-03

Liamuiga, a stratovolcano on the island of St. Kitts, has had four Holocene eruptions and two unconfirmed historic eruptions. The dates for the prehistoric eruptions range from 2320 B.C.E. to 150 C.E.. Three of these eruptions were Plinian in style. The unconfirmed historic eruptions were in 1692 and 1843. Pyroclastic flows are common during Liamuiga's eruptions.

Table 1c. LIAMUIGA

Nevis Peak17.15N62.58W 985m1600-04

Nevis Peak is a Holocene stratovolcano with no historic eruptions.

Soufriere Hills16.72N63.18W 915m1600-05

Soufriere Hills, a stratovolcano on the island of Montserrat, began erupting on July 18, 1995. This is the first recorded eruption of this volcano in historic time although Soufriere Hills has erupted 6 times since its first in 1630. The initial small phreatic eruption produced minor ash that spread around the island. Periods of intense seismic activity were associated with strong venting of steam and ash. A new vent formed south-west of Castle Peak, an old volcanic dome.The latest eruption of the Soufriere Hills volcano occurred on 18th July 1995 and has been erupting on and off since then and continues as of this report.

Table 1d. SOUFRIERE HILLS

La Soufrière16.05N61.67W1,467m1600-06 (Guadeloupe)

La Soufrière is also a stratovolcano with a summit dome, on the southern part of the island of Guadeloupe. It has erupted a total of 22 times since 6550 B.C.E. and explosively 12 times since 1300 C.E.. The last eruption, which was in 1976, prompted the evacuation of over 70,000 citizens of the island for several months. As it turned out, most of the 1976 eruptions were considered minor in nature.

Table 1e. SOUFRIERE (Guadeloupe)

(Unnamed)15.97N61.43W -45m1600-07

This unnamed submarine volcano is thought to be a submarine geyser or perhaps a karst collapse. This occurred in the Pleistocene era.

Table 1f. UNNAMED

Morne Au Diable15.62N61.45W 861m1600-0

Dominica is part of the Lesser Antilles island arc that marks a convergent plate tectonic boundary between the Caribbean and Atlantic plates. The island of Dominica consists mostly of breccias, domes, pyroclastic flows, and lavas derived and erupted from at least seven volcanic centres. Volcano Morne Au Diable is fumarolic and has had no historical eruptions.

Morne Diablotins15.50N61.42W 1,430m1600-09

Similar to Morne Diable, the Morne Diablotins volcano is fumarolic in nature and has had no historical eruptions. Morne Diablotins is located in the north-central part of the island of Dominica and is the highest peak on the island and the second highest volcano in the Lesser Antilles.

Microtin15.33N61.33W 1,387m1600-10 Morne Trois Pitons

This volcano in the south-western Dominica is between the islands of Guadeloupe and Martinique. Microtin itself is a prominent lava dome 9 km north-east of Dominica’s capital city, Roseau, and is believed to be the source of Roseau ash, the largest recent tephra deposit in the West Indies. The volcano’s only historic eruption, which occurred at the Valley of Desolation solfatara field, was in 1880 (McClelland, et al, 1989). However, there have been several episodes of seismic unrest. Part of the source of the basal and major ignimbrite deposit may lie beneath the large Morne Trois Piton dome complex, whereas the source of the younger pyroclastic deposits is probably beneath the younger Microtin dome, immediately south of Morne Trois Piton.

Morne Patates15.22N61.37W 960m1600-11

In the southern part of Dominica, where recent seismic activity (1997-98) has been intense and of considerable concern, there are six Quaternary to recent volcanic centres in close proximity. Morne Patates is the youngest of these centres, with the last eruption dated at 1500 C.E.. The 3 Km diameter centre consists of a pair of andesitic domes situated within a structural depression.

Table 1g. MORNE PATATES

Montagne Pelée14.82N61.17W 1,397m1600-12

A stratovolcano with summit domes on the island of Martinique in the French West Indies. The devastating and explosive eruption of the 8th of May in 1902, the third most disastrous volcanic eruption of all time, generated a nuée ardente that swept down the side of the volcano and within minutes completely destroyed the town of St. Pierre and its 28,000 inhabitants (Decker & Decker, 1989) . Three other explosive eruptions have been noted and recorded, the last occurred in 1929 and lasted until 1932. Mt. Pelée has erupted a total of 53 times since 7225 B.C.E..

Table 1h. Mt. PELÉE

# / Year / C
e
n
t
r
a
l / F
l
a
n
k
V
e
n
t / R
a
d
i
a
l
f
i
s / R
e
g
i
o
n
a
l / S
u
b
m
a
r
i
n
e / N
e
w
I
s
l
a
n
d / S
u
b
g
l
a
c
i
a
l / C
r
a
t
e
r
L
k / E
x
p
l
o
s
i
v
e / P
y
r
o
F
l
o
w / P
h
r
e
a
t
i
c / F
u
m
a
r
o
l
i
c / L
a
v
a
F
l
o
w / L
a
v
a
L
a
k
e / D
o
m
e / S
p
i
n
e / F
a
t
a
l / D
a
m
a
g
e / M
u
d
f
l
o
w / T
s
u
n
a
m
i
1 / -7225.0 / X / X / X
2 / -6445.0 / X / X / X / X
3 / -6090.0 / X / X / X
4 / -5795.0 / X / X / X
5 / -544.0 / X / X / X
6 / -4680.0 / X / X / X
7 / -3820.0 / X / X / X
8 / -3700.0 / X / X / X / X
9 / -3495.0 / X / X / X
10 / -3290.0 / X / X / X
11 / -3245.0 / X / X / X / X
12 / -3150.0 / X / X / X / X
13 / -3015.0 / X / X / X / X
14 / -2660.0 / X / X / X
15 / -2560.0 / X / X / X / X
16 / -2460.0 / X / X / X
17 / -2425.0 / X / X / X
18 / -2360.0 / X / X / X / X
19 / -2275.0 / X / X / X
20 / -2110.0 / X / X / X
21 / -2025.0 / X / X / X
22 / -1760.0 / X / X / X
23 / -1180.0 / X / X / X
24 / -0800.0 / X / X / X
25 / -0725.0 / X / X / X
26 / -0615.0 / X / X / X
27 / -0600.0 / X / X / X
28 / -0540.0 / X / X / X / X
29 / -0495.0 / X / X / X
30 / -0440.0 / X / X / X
31 / -0310.0 / X / X / X
32 / -0195.0 / X / X / X
33 / -0065.0 / X / X / X
34 / 0050.0 / X / X / X
35 / 0125.0 / X / X / X
36 / 0220.0 / X / X / X / X
37 / 0280.0 / X / X / X
38 / 0300.0 / X / X / X
39 / 0445.0 / X / X / X
40 / 0645.0 / X / X / X
41 / 0720.0 / X / X / X
42 / 0810.0 / X / X / X
43 / 0910.0 / X / X / X
44 / 1185.0 / X / X / X
45 / 1260.0 / X / X / X
46 / 1300.0 / X / X / X
47 / 1370.0 / X / X / X
48 / 1460.0 / X / X / X
49 / 1635.0 / X / X / X / ?
50 / 1792.0 / X / X / X
51 / 1851.7 / X / X / X / X
52 / 1902.3 / X / X / X / X / X / X / X / X / X / X / X / X
53 / 1929.8 / X / X / X / X / X / X / X

Hodder’s Volcano14.03N61.07W-----1600-13(Not a volcano.)

This volcano is listed in the catalogue as a volcano but is, in fact, not a volcano. It is commented on here for completeness.

Qualibou13.83N61.05W 777m1600-14

The Qualibou volcano is a caldera that has had only one eruption in the Sulphur Springs area

of the island and this occurred in 1766. The Sulphur Springs consist of three discrete areas of

fumarolic activity, of which the highest one is the largest.

Table 1i. QUALIBOU

Soufriere13.33N61.18W 1,220m1600-15 (St. Vincent)

Volcano Soufriere is a stratovolcano, on the island of St. Vincent with a crater lake. It’s seven eruptions since 1718 have included 2 major explosive eruptions, one in 1902 (at the same time that Mt. Pelée erupted) and the other in 1979. Evacuation of the citizens of the north end of the island in 1979 helped prevent a repeat of the tragic eruption of 1902 whereby 1,600 deaths occurred, most of which were as a result of nuées ardentes. Soufriere, on St. Vincent, has erupted a total of 22 times in its history from 2380 B.C.E. .

Table 1j. SOUFRIERE (St. Vincent)

Kick-‘em Jenny12.30N61.63W -160m1600-16

Kick-'em-Jenny is a submarine volcano located 6 miles (10 km) north of the island of Grenada. It is the southern-most live volcano in the Lesser Antilles volcanic arc and the only live submarine volcano in the arc. Kick-'em-Jenny and the other volcanoes in the arc are associated with a subduction zone. The subduction zone is formed by an oceanic plate created at the Mid-Atlantic Ridge as it is pushed under the Caribbean Plate. The volcano is near Calle Island and is made of two youthful craters and lava flows. Kick-'em-Jenny has erupted 12 times since 1939 with the most recent eruption in 2001. The 1939 eruption sent a black cloud up to 885 feet (270 m) above sea level. During the 1965 eruption, earthquakes of intensity V were felt on Isla de Ronde. During the 1974 eruption, the sea above the volcano was boiling turbulently and spouting steam. Most of the eruptions were detected by submarine hydrophones. The hydrophones detect shock waves from explosive eruptions as they travel through the water. Using data from several hydrophones, volcanologists can determine where a live submarine volcano is located and when it started erupting. There is indication that eruptions at Kick-'em-Jenny are hazardous due to the fact that tsunamis may develop. Kick-'em-Jenny has a basal diameter of about 3 miles (5 km) and rises about 4,300 feet (1,300 m) above the sea floor. Oceanographic surveys found a crater at the summit of the volcano and retrieved samples of fresh olivine basalt pyroclasts.

Table 1k. KICK ‘EM JENNY

# / Year / C
e
n
t
r
a
l / F
l
a
n
k
V
e
n
t / R
a
d
i
a
l
f
i
s / R
e
g
i
o
n
a
l / S
u
b
m
a
r
i
n
e / N
e
w
I
s
l
a
n
d / S
u
b
g
l
a
c
i
a
l / C
r
a
t
e
r
L
k / E
x
p
l
o
s
i
v
e / P
y
r
o
F
l
o
w / P
h
r
e
a
t
i
c / F
u
m
a
r
o
l
i
c / L
a
v
a
F
l
o
w / L
a
v
a
L
a
k
e / D
o
m
e / S
p
i
n
e / F
a
t
a
l / D
a
m
a
g
e / M
u
d
f
l
o
w / T
s
u
n
a
m
i
1 / 1939.5 / X / X
2 / 1943.8 / X
3 / 1953.8 / X
4 / 1965.8 / X
5 / 1966.4 / X
6 / 1972.5 / X
7 / 1974.8 / X
8 / 1977.0 / X
9 / 1988.9 / X / X / X
10 / 1990.2 / X
11 / 2001.5 / X

St. Catherine12.15N61.67W 840m1600-17

Volcano St. Catherine is considered a Holocene volcano and has had no eruptions in historic time. It is the last volcano in the Lesser Antilles chain of volcanoes and islands.

Of the 17 volcanoes of the Lesser Antilles listed in the “Volcanoes of the World”, 2nd Edition by T. Simkin & L. Siebert (1994), only 14 of those volcanoes have erupted repeatedly in the last 10,000 years. Dominica has at least three live volcanoes and is the most active island in the arc, although the least well known volcanologically. However, compared to many other island arcs the Lesser Antillean volcanism in not particularly vigorous. There are now only five volcanoes that have erupted new magma during the recorded history of the last 300 years: Kick-‘em-Jenny, Soufriere (St. Vincent), Mt. Pelée (Martinique), La Soufriere (Guadeloupe) and most recently, Soufriere Hills (Montserrat). The near simultaneous eruptions of Soufriere (St. Vincent) and Mt. Pelée in 1902 caused approximately 28,000 deaths where persons were killed by devastating pyroclastic flows and surges, most in the village of St. Pierre located on the south-western flank of Mt. Pelée. Subsequent study of the eruptive behaviour and deposits of both volcanoes has made them excellent type examples of basaltic pyroclastic and dome/crater lake growth (Soufriere), and andesitic block/ash flows (Mt. Pelée).

There are two other types of activity that have occurred at the volcanoes of the Lesser Antilles arc during the historic period; phreatic eruptions and seismic crises. Phreatic eruptions are usually small explosive eruptions involving steam and old rock fragments. The eruption of La Soufrière (Guadeloupe) in 1976-77 which caused the evacuation of the town of Basse Terre for a period of several weeks, was of this type – probably caused by magma rising within the volcano after heating the groundwater. Seismic crises are even more common and typically involve tens to hundreds of small earthquakes at depths of a few kilometres as rising magma deforms the lower levels of the volcanoes.

With respect to all the live volcanoes of the Lesser Antilles, only those volcanoes with sufficient data, including eruptive history, will have forecasts as generated by ERUPTION Pro 10.3 volcano forecasting software.

Table II presents the overall summary forecast for those volcanoes listed as volcanoes of the Lesser Antilles. Only those with sufficient data have probability[2] in the years indicated shown. All others, with insufficient data are marked as “Not Forecasted”.

Table III presents the probability2 forecast with respect to the volcano’s 50% probability of an event in the year indicated analysis. In this analysis, ERUPTION Pro 10.3 determines the year whereby the volcano is forecasted to have an event with 50% probability.

Table IV presents the probability2 forecast with respect to the volcano’s repose analysis in the year indicated. The repose analysis is a special routine of ERUPTION Pro 10.3 and as such indicates the forecasted events of the volcanoes indicated based solely on their repose periods to date.

The current indication from the analyses performed shows that volcano SOUFRIERE HILLS on Montserrat followed by KICK ‘EM JENNY just above Grenada are the next two volcanoes to have an eruptive event. Current reliability analysis of ERUPTION Pro 10.3 indicates a reliability of 92.6%, i.e., ERUPTION Pro 10.3 is correct 92.6% of the time and only 7.4% incorrect with its forecasts.

LITERATURE CITED

Donovan, S. K. & Jackson, Trevor A., 1994, “Caribbean Geology, An Introduction”, Pgs. 167– 177

Sigurdsson, H. & Carey, S., 1991, “Caribbean Volcanoes: A Field Guide”

McClelland, L., Simkin, T., Summers, M., Nielsen, E., & Stein, T., 1989, “Global Volcanism 1975-1985”, Smithsonian Institution Scientific Event Alert Network (SEAN), Pgs. 541-554

4. Case, J. E., 1975, Geophysical Studies in the Caribbean Sea: in Nairn, A.E.M. & Stehli, F.G.

(eds.), “The Ocean Basins and Margins. 3. The Gulf of Mexico and the Caribbean”. Plenum, New York, Pgs. 107-111

Trombley, R. B. , 1998, "An Improved Statistical Long-Range Volcano Eruption Forecasting

Programme, 'ERUPTION' Pro 9.6”, Transactions of the 15th Caribbean Geological Conference, University of the West Indies, Kingston, Jamaica, 29 June – 2 July 1998

6. Trombley, R. B. , 2002, " Eruption Pro 10.3 – The New & Improved Long-Range

Eruption Forecasting Software”, Transactions of the 16th Caribbean Geological

Conference, Barbados, 16 June – 21 June 2002

T. Simkin & L. Siebert, “Volcanoes Of The World”, 2nd Edition, 1994, Geosciences Press,

Pages 150-152

Decker, R. & Decker, B., 1989, “Volcanoes”, Revised and Updated Edition, Pg. 252

[1] Dr. Robert B. Trombley is currently the Principal Research Volcanologist at the Southwest Volcano Research Centre and is Professor Emeritus with DeVRY University, Phoenix, Arizona.

e-mail:

[2] In accordance with current ERUPTION Pro 10.3 forecasting techniques.