Solomon Islands Region Research Articles

Subseasonal prediction framework for tropical cyclone activity in the Solomon Islands region

AbstractRecently, we developed seasonal prediction schemes with improved skill to predict tropical cyclone (TC) activity up to 3 months in advance for the Solomon Islands (SI) region (5°–15°S, 155°–170°E) using sophisticated Bayesian regression techniques. However, TC prediction at subseasonal timescale (i.e., 1–4 weeks in advance) is not being researched for that region despite growing demands from decision makers at sectoral level. In this paper, we first assess the feasibility of developing subseasonal prediction frameworks for the SI region using a pool of predictors that are known to affect TC activity in the region. We then evaluate multiple predictor combinations to develop the most appropriate models using a statistical approach to forecast weekly TC activity up to 4 weeks in advance. Predictors used include indices of various natural climate variability modes, namely the Madden–Julian Oscillation (MJO), the El Niño–Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD) and the Interdecadal Pacific Oscillation (IPO). These modes often have robust physical and statistical relationships with TC occurrences in the SI region and the broader southwest Pacific territory as shown by preceding studies. Additionally, we incorporate TC seasonality as a potential predictor given the persistence of TCs occurring more in certain months than others. Note that a model with seasonality predictor alone (hereafter called the “climatology” model) forms a baseline for comparisons. The hindcast verifications of the forecasts using leave‐one‐out cross‐validation procedure over the study period 1975–2019 indicate considerable improvements in prediction skill of our logistic regression models over climatology, even up to 4 weeks in advance. This study sets the foundation for introducing subseasonal prediction services, which is a national priority for improved decision making in sectors like agriculture and food security, water, health and disaster risk mitigation in the Solomon Islands.

Tropical cyclone activity in the Solomon Islands region: Climatology, variability, and trends

AbstractThis study examines the climatology, variability, and trends of tropical cyclones (TCs) affecting the Solomon Islands (SI) territory, in the wider southwest Pacific (SWP), using the South Pacific Enhanced Archive for Tropical Cyclones (SPEArTC) database. During the period 1969/1970–2018/2019, 168 TCs were recorded in the SI territory. A cluster analysis is used to objectively partition these tracks into three clusters of similar TC trajectories to obtain better insights into the effects of natural climate variability, particularly due to the El Niño–Southern Oscillation (ENSO) phenomenon, which otherwise is not very apparent for TCs when considered collectively in the SI region. We find that TCs in clusters 1 and 3 show enhanced activity during El Niño phase, whereas TCs in cluster 2 are enhanced during La Niña and neutral phases. In addition to being modulated by ENSO, TCs in clusters 2 and 3 show statistically significant modulation at an intraseasonal timescale due to the Madden–Julian Oscillation (MJO) phenomenon. There are also some indications through sophisticated Bayesian modelling that TCs in clusters 2 and 3 are slightly influenced by the Interdecadal Pacific Oscillation (IPO). These results can have substantial implications for cluster‐specific development of TC prediction schemes for the SI region.

Medicinal Properties of Ant Nest Plant (Myrmecodia Genus): A Comprehensive Review

BACKGROUND: The Myrmecodia genus belongs to the Rubiaceae family, which has the characteristic of an epiphytic plant. This genus spread from Malaysia, through the Philippines, Sumatra, Borneo, Java, New Guinea (Papua), Cape York to the Solomon Islands and Pacific region. It has been empirically proven to treat gout, inflammation, muscle pain relief, strengthen the body’s immunity, and cancer treatment. AIM: This article reviewed the scientific work about the Myrmecodia genus concerning their traditional uses, phytochemical compounds, and pharmacological activities of Myrmecodia. METHODS: The sources were from the scientific literature online database, including Science Direct, PubMed, and Google Scholar between 1978 and 2021. Furthermore, 112 articles were collected, while 61 full-text were assessed for eligibility. RESULTS: The Myrmecodia extract has many pharmacological activities, namely antioxidant, antibacterial, cytotoxic, and anticancer. CONCLUSION: Moreover, this review may be used as scientific literature for the next investigations on the genus Myrmecodia, especially regarding pharmacological properties such as in vitro and in vivo studies and isolation of the active compounds.

Food Purchasing Behaviors of a Remote and Rural Adult Solomon Islander Population.

The aim of this study was to investigate the food purchasing behaviors of an adult Solomon Islander population within a transitioning food system in Auki, Malaita. Food purchasing behavior measures included; venue type and transportation for purchasing food, previous day expenditure on food purchases, number of weekly shopping experiences for store foods (generally long-life shelf and frozen items) and fresh foods (such as fruits and vegetables and fresh fish) and the importance of factors (i.e., price) on purchasing decisions. One hundred and thirty-three adults (aged 18 to 74 years; female: 63%, males: 37%) completed an interviewer administered questionnaire during December 2018. Food items were primarily sourced from Auki markets (n = 70) and stores (n = 40). Food purchasing differed between fresh and semi-perishable foods (store food). Participants reported similar shopping experiences for store food and fresh food (M = 3.87 and M = 3.25 times a week, respectively) and spending between $1 and $200 (M = $56.12) Solomon Island dollars on food in the previous day. The most reported purchased item was white rice (n = 117, 88%), with taste, freshness and family preference the most important factors reported as influencing food purchasing choices. While our findings are from a small sample in Auki, further research could build upon this work by investigating food purchasing behaviors at other times of the year, and more widely in the Solomon Islands and greater Pacific region.

Tectonic evolution and copper-gold metallogenesis of the Papua New Guinea and Solomon Islands region

Papua New Guinea and the Solomon Islands are in one of the most prospective regions for intrusion-related mineral deposits. However, because of the tectonic complexity of the region and the lack of comprehensive regional geological datasets, the link between mineralization and the regional-scale geodynamic framework has not been understood. Here we present a new model for the metallogenesis of the region based on a synthesis of recent studies on the petrogenesis of magmatic arcs and the history of subduction zones throughout the region, combined with the spatio-temporal distribution of intrusion-related mineral deposits, and six new deposit ages. Convergence at the Pacific-Australia plate boundary was accommodated, from at least 45 Ma, by subduction at the Melanesian trench, with related Melanesian arc magmatism. The arrival of the Ontong Java Plateau at the trench at ca. 26 Ma resulted in cessation of subduction, immediately followed by formation of Cu-Au porphyry-epithermal deposits (at 24–20 Ma) throughout the Melanesian arc. Late Oligocene to early Miocene tectonic reorganization led to initiation of subduction at the Pocklington trough, and onset of magmatism in the Maramuni arc. The arrival of the Australian continent at the Pocklington trough by 12 Ma resulted in continental collision and ore deposit formation (from 12 to 6 Ma). This is represented by Cu-Au porphyry deposits in the New Guinea Orogen, and epithermal Au systems in the Papuan Peninsula. From 6 Ma, crustal delamination in Papua New Guinea, related to the prior Pocklington trough subduction resulted in adiabatic mantle melting with emplacement of diverse Cu and Au porphyry and epithermal deposits within the Papuan Fold and Thrust Belt and Papuan Peninsula from 6 Ma to the present day. Subduction at the New Britain and San Cristobal trenches from ca. 10 Ma resulted in an escalation in tectonic complexity and the onset of microplate tectonics in eastern Papua New Guinea and the Solomon Islands. This is reflected in the formation of diverse and discrete geodynamic settings for mineralization within the recent to modern arc setting, primarily related to upper plate shortening and extension and the spatial relationship to structures within the subducting slab.

Geochemical Characterization of Lapita Ceramics From the Western Solomon Islands by Means of Portable X-Ray Fluorescence and Scanning Electron Microscopy

ABSTRACTThe study of interaction and exchange among different geographic areas in the Western Pacific occupied by Lapita people (3500–2500 BP) has been an important component of research into the colonization process of the Pacific region. The Western Solomon Islands, lying in the central area of the Lapita distribution, have a unique archaeological record presenting intertidal sites with Late/Post Lapita ceramics as the only material evidence of Lapita occupation. Previous studies have indicated that Lapita ceramic production was mainly local. However, temper analysis has identified exotic ceramics in Late Lapita sites in the New Georgia Group, indicating complex ceramic transfer including from outside the Solomon Islands region. Analysis of Late Roviana (New Georgia) and historic period ceramic sherd temper has also suggested ceramic transfer from the nearby island of Choiseul, where ceramics were manufactured until recent times. Here we present results of a series of portable X-ray fluorescence and Scanning Electron Microscopy analyses carried out on ceramic pastes from the New Georgia group in the Western Solomon Islands. These results confirm that during the Early (Lapita/Post Lapita) ceramic period, production was present at multiple locations and that ceramics were transferred at different geographic scales involving occasional long-distance interactions. During the later period (AD 1400–1900) ceramic production had a more restricted occurrence with transfer networks changing and receding to become exclusively regional.

Estimating parent population of pottery vessels from a sample of fragments: a case study from inter-tidal surface collections, Roviana Lagoon, Solomon Islands

Archaeologists frequently interpret the duration and type of prehistoric occupation at a location/site from the relative abundance of prehistoric materials (accumulations research). Taphonomic factors have the potential to alter substantially the archaeological record leading to inaccurate assumptions about the nature of prehistoric settlement. Where vessel families of potsherds can be established, we provide a general method to estimate the parent population from which the sample of sherds derives, through analysis of vessel completeness of the sample. This provides a basis for archaeological interpretation of the scale of discard represented at a location. The approach used has broad applicability to many archaeological settings where behavioural inferences are made from poorly preserved ceramic samples. Statistical analysis of a ceramic assemblage from Roviana Lagoon stilt villages indicates that most of the ceramic assemblage has been destroyed over time. An unexpectedly severe taphonomic regime is inferred for this relatively sheltered landlocked lagoon setting. Rather than marking an ephemeral occupation, estimating a parent ceramic population indicates instead that early stilt village sites in the Solomon Islands region were probably permanently occupied for several centuries. Results also suggest that the relative absence of recorded Lapita sites in the main Solomon Islands, and possibly elsewhere in Near Oceania may be a result of a harsh taphonomic regime for the remains of stilt village occupation.

Oscillatory and Propagating Modes of Temperature Variability at the 3–3.5- and 4–4.5-yr Time Scales in the Upper Southwest Pacific Ocean

Abstract This paper investigates oscillatory and propagating patterns of normalized surface and subsurface temperature anomalies (from the seasonal cycle) in the southwest Pacific Ocean using an extended empirical orthogonal function (EEOF) analysis. The temperature data (and errors) are from the Digital Atlas of Southwest Pacific upper Ocean Temperatures (DASPOT). These data are 3 monthly in time (January, April, July, and October), 2° × 2° in space, and 5 m in the vertical to 450-m depths. The temperature anomalies in the EEOF analysis are normalized by the objective mapping temperature errors at each grid point. They are also Butterworth filtered in the 3–7-yr band to examine interannual variations in the temperature field. The oscillating and propagating patterns of the modes are examined across four vertical levels: the surface, and 100-, 250-, and 450-m depths. The dominant mode EEOF (70% of the total variance of the filtered data) oscillates in a 4–4.5-yr quasi-periodic manner that is consistent with El Niño–Southern Oscillation (ENSO). Anomalies peak first at the surface in the subtropics between New Caledonia and Fiji (centered around 17°S, 177°E), then 6 months later in the tropical far west centered around the Solomon Islands (5°S, 153°–157°E), with a maximum at the base of the mixed layer (100 m) and upper thermocline (250 m), and then eastward in the northeast of the southwest Pacific region (0°–10°S, 160°E–180°). Mode 2 (25% variance of the filtered data) has a periodicity of 3–3.5 yr, with centers of action in all four vertical levels. The mode-2 patterns are consistent with variations in the subtropical gyre circulation, including the East Australian Current and its separation, and are continuous with the Tasman Front. Two spatial dipoles are apparent: (i) one in sea surface temperature (SST) at about 5°S, straddling west–east either side of the Solomon Islands, consistent with the classic Pacific-wide ENSO SST anomaly mode, and (ii) a subsurface dipole pattern, with centers in the Solomon Islands region at 100- and 250-m depths, and the western Tasman Sea (27°–33°S, 157°–161°E) at 250- and 450-m depths, consistent with dynamic changes in the gyre intensity.

Subduction of the Woodlark Basin at New Britain Trench, Solomon Islands region

The Woodlark Basin, located south of the Solomon Islands arc region, is a young (∼5 Ma) oceanic basin that subducts beneath the New Britain Trench. This region is one of only a few subduction zones in the world where it is possible to study a young plate subduction of several Ma. To obtain the image of the subducting slab at the western side of the Woodlark Basin, a 40-day Ocean Bottom Seismometer (OBS) survey was conducted in 1998 to detect the micro-seismic activity. It was the first time such a survey had been performed in this location and over 600 hypocenters were located. The seismic activity is concentrated at the 10–60 km depth range along the plate boundary. The upper limit just about coincides with the leading edge of the accretionary wedge. The upper limit boundary was identified as the up-dip limit of the seismogenic zone, whereas the down-dip limit of the seismogenic zone was difficult to define. The dip angle of the plate at the high seismicity zone was found to average about 30°. Using the Cascadia subduction zone for comparison, which is a typical example of a young plate subduction, suggests that the subduction of the Woodlark Basin was differentiated by a high dip angle and rather landward location of the seismic front from the trench axis (30 km landward from the trench axis). Furthermore, as pointed out by previous researchers, the convergent margin of the Solomon Islands region is imposed with a high stress state, probably due to the collision of the Ontong Java Plateau and a rather rapid convergence rate (∼10 cm/year). The results of the high angle plate subduction and inner crust earthquakes beneath the Shortland Basin strongly support the high stress state. The collision of the Ontong Java Plateau, the relatively rapid convergence rate, and moderately cold slab as evidenced by low heat flow, rather than the plate age, may be dominantly responsible for the geometry of the seismogenic zone in the western part of the Woodlark Basin subduction zone.

Polarity reversal in the Solomon Islands arc

McKenzie1 proposed that the direction of subduction beneath an island arc will reverse following arc–continent collision. Dewey and Bird2 suggested that such an arc polarity reversal occurred in northern New Guinea; Johnson and Molnar3, however, proposed two alternative models of plate convergence that could explain the observed seismicity. We present here a spatial seismicity study of the Solomon Islands region which has revealed the existence of two juxtaposed Wadati–Benioff (W–B) zones of opposite polarity. Shallow and intermediate foci define a north-east-dipping W–B zone associated with active subduction along the New Britain and San Cristobal trenches and a south-west-dipping W–B zone associated with the inactive North Solomon trench (NST). These data provide the first direct seismic evidence of a reversal in subduction polarity at an island arc.

Upper mantle velocity structure in the New Guinea and Solomon Islands regions.

Upper mantle velocity structure in the New Guinea-New Britain-Solomon Islands regions of the Southwest Pacific has been studied to a depth of about 550 km from the analysis of P and S wave travel times data of 128 mantle earthquakes. Wave velocities were obtained at the depths of foci of earthquakes in the inclined seismic zones in these regions, by using KAILA'S (1969) analytical method. By a linear fitting of velocity variation with depth, it is found that the P velocity in the New Guinea region increases from 7.92 km/s at 40 km depth to 8.26 km/s at 230 km depth. On the other hand, the P velocity function for the Solomon Islands region reveals a velocity of 7.80 km/s at 40 km depth which increases, with a velocity gradient of 0.280±0.003 km/s per 100 km, to 8.81 km/s at a depth of 400 km. At this transition depth of 400 km, there is a sharp first-order velocity discontinuity-the velocity increasing from 8.81 to 9.44 km/s which is about a 7.2 % velocity increase across this discontinuity. Below this disco tinuity at 400 km, P velocity increases again from 9.44 km/s, with a gradient of 0.230±0.035 km/s per 100 km, to 9.77 km/s at a depth of 545 km. There is no evidence, from the present study, for the presence of a significant low-velocity layer in the inclined seismic zones beneath the New Guinea-New Britain-Solomon Islands regions. The velocities obtained in the Solomon Islands region are 3 to 6 % (on an average) higher and lower, respectively, than those in the Japan and the Tonga-Kermadec regions.

Preliminary Results of Leg 3 Lee Cruise--Basin Development and Resource Potential of Central Solomons Trough: ABSTRACT

A CCOP/SOPAC cruise funded by Australia, New Zealand, and the United States surveyed parts of the Solomon Islands region in May and June 1982, in order to assess the potential for petroleum accumulations and to identify geologic hazards. Work was concentrated in the central Solomons trough (the Slot) between the islands of Guadalcanal, Santa Ysabel, New Georgia, and Choiseul, where continuous multichannel, single channel, and high resolution seismic records were acquired together with magnetic and gravity profiles. The Slot is underlain by a composite depositional basin that contains as much as 2.8 mi (4.5 km) of Cenozoic sediments. Despite its complex island-arc setting, submarine volcanoes, and 2,625 to 5,900 ft (800 to 1,800 m) water depths, the basin includes structural, stratigraphic, and possibly thermal elements that favor generation and entrapment of hydrocarbons. End_of_Article - Last_Page 986------------

Earthquake doublets in the Solomon Islands

Large, shallow, thrust earthquakes in the Solomon Islands region tend to occur in closely related pairs. Two recent sequences are July 14, 1971 ( M S = 7.9) and July 26, 1971 M( S = 7.9) and 14 h37 m, July 20, 1975 ( M S = 7.9) and 19 h54 m, July 20, 1975 ( M S = 7.7). The mechanism of these seismic doublets has important bearing on the triggering mechanism of earthquakes in subduction zones. Detailed analysis of the seismic body waves and surface waves were performed on the 1971, 1974, and 1975 doublets, providing a better understanding of: (1) the mechanics of seismic triggering, (2) the state of stress on the fault plane, and (3) the nature of subduction between the Pacific and Indian plates. The results indicate that although the geometry of the subduction zone in the Solomon Islands is complicated by the presence of several sub-plates, the slip direction of the Indian plate with respect to the Pacific plate is relatively uniform over the entire region. The large seismic moments of the 1971 sequence (1.2 · 10 28 and 1.8 · 10 28 dyne cm) indicate that these events directly represent the underthrusting of the Indian and Solomon plates beneath the Pacific plate. The body waves from these doublets, recorded on the WWSSN long-period seismograms, are remarkably impulsive and simple compared with those from events of comparable seismic moment in other subduction zones. In addition, the source dimensions of the body waves are 30–70 km in length, substantially smaller than the overall rupture surfaces radiating the surface waves which are 100–300 km in length. These facts suggest the existence of relatively large, isolated high-stress zones on the fault plane. This type of stress distribution is distinct from other regions which have more heterogeneous stress distribution on the fault plane, and this is proposed as the principal characteristic of this region responsible for the occurrence of the doublets and for the apparent efficiency of triggering in the Solomon trench. Prior to the 1971 sequence, similar sequences have occurred in the same area in 1919–1920 and 1945–1946. From the amount of slip (1.3 m) determined for the 1971 sequence and the apparent recurrence interval of 25 years, a seismic slip rate of 5 cm yr −1 is determined. This value is a significant portion of the convergence rate between the Indian and Pacific plates indicating that the plate motion here is taken up largely by seismic slip.

Seismotectonics of the Papua New Guinea—Solomon Islands region

Earthquakes for the period 1964–1973 are relocated by the method of Joint Hypocenter Determination in order better to resolve the configuration and the structure of the New Guinea—New Britain—Solomon Islands region. Focal mechanism solutions are integrated with the seismicity and interpreted closely with it. A zone of subduction exists beneath New Britain and the Solomon Islands, a zone of left-lateral strike-slip movement extends from New Ireland to New Guinea. The zone of seismicity in northern New Guinea has developed as a result of a continent—island-arc collision in late Oligocene—Miocene times and does not exhibit a well-developed inclined seismic zone. It is proposed that plate tectonics theory does not apply rigorously, but slip-line field theory allows the presentation of a new geodynamic model for this region.

Part 6. Present plate boundary seismic, volcanic and kinematic processes: Distribution of underthrust lithosperic slabs and focal mechanisms – Papua New Guinea and Solomon Islands region

Studies of the spatial distribution of shallow earthquakes define the present day plate boundaries. In the Papua New Guinea and Solomon Islands region (PNGS) these are well determined and indicate a mozaic of several small plates each moving relatively to the other (see fig. 1). Some of the boundaries are zones of plate convergence where lithospheric material is being thrust (or sinks) deep into the mantle. These regions are indicated by earthquakes occurring at depths greater than 100 km.

Part 6. Present plate boundary seismic, volcanic and kinematic processes: Seismicity and earthquake focal mechanisms in the New Guinea Solomon Islands region

There is general agreement between plate tectonic theory and seismicity for the New Guinea Solomon Islands region. Two minor plates, the Solomon Sea and South Bismarck plates, are sandwiched within the collision zone between the continental fronts of the Pacific and India plates, and derive their relative motions from the collision. The azimuth of collision is approximately east?northeast.

Large earthquakes in the New Guinea-Solomon Islands area, 1873–1972

A catalogue of 1873–1972 earthquakes with M > 6.9 for the New Guinea—Solomon Islands region (130–165° E) is compiled. There are 152 events listed. Duda's (1965) results for 1900–1968 are improved for the Papua New Guinea area (141–156° E) because of the availability of historical data for that area. Although there is evidence of rapid Holocene uplift in the main seismic zones, there is little historical evidence for visible uplift or subsidence resulting directly from modern major earthquakes. Coastal subsidences commonly reported as a result of earthquakes are of smaller extent and appear to be due to settlement. However, the occurrence of tsunamigenic earthquakes does suggest that surface deformations do take place off-shore. Using Davies and Brune's (1971) method, regional fault slip rates over 5° -segments of the shallow seismic zone are determined from the seismicity catalogue. The slip rate for the island of New Guinea (Gutenberg and Richter's Region 16) is found to be at least 4.4 cm/y which is almost double the very anomalously low rate of 2.3 cm/y found by Davies and Brune (1971). If allowance is made for shear movement without seismicity and for the approximately 2 1 ratio of dip-slip versus strike-slip faulting indicated by fault plane solutions, the agreement with Le Pichon's (1970) approach value of 10.7 cm/y for the Pacific—India (Australia) plates is reasonable. The fault slip rate in the area between east New Britain and Bougainville at the Pacific—Bismarck—Solomon triple junction is extremely high (20.6 cm/y at least). The smallest slip rate (1.5 cm/y) is found for westernmost New Guinea (130–135° E). Temporal cumulative summation of moments curves show a periodicity of approximately 25 years in the seismic activity at the triple junction (150–155° E). Elsewhere the rate of seismic activity is aperiodic.

The spatial seismicity of Papua New Guinea and the Solomon Islands

Abstract The spatial distribution of earthquakes is described for the Papua New Guinea and Solomon Islands region, using data for the period 1931 to 1970. Most of the seismic activity is concentrated in a belt which follows through northern New Guinea, New Britain, Bougainville, and the Solomon Islands. Within this belt, the activity is highest from the Huon Peninsula to the southern end of Bougainville. Here, there is evidence that the earthquake foci lie in zones which dip away from the Solomon Sea, with a series of deep earthquakes occurring on the northern side of the main seismic axis. This section also marks the region of greatest apparent energy and strain release. In northern New Guinea the activity generally increases from west to east, as do the focal depths of the deepest earthquakes. Although the pattern is not clear, the earthquakes appear to lie within a zone which dips towards the northeast, although, in parts, there is also evidence that some reside in another zone which dips less steeply ...

Plate tectonics and the Papua—New Guinea—Solomon Islands region

Abstract The focal mechanism solutions for a number of earthquakes in the New Guinea region are presented. These solutions, together with the results of a previously reported spatial seismicity study, are used to deduce the tectonic nature of the region in terms of plate tectonics, using the geological features of the region as constraints. The region is basically a zone of interaction of the Australian and South Pacific plates. Within this zone are several minor sub-plates referred to as the Solomon Sea, New Britain, and Manus plates. A consistent system of relative velocity vectors has been deduced for these plates. A zone of subduction is apparent under New Britain and the Solomon Islands, a zone of sinistral transcurrent movement operates between the New Britain and Manus plates, sea-floor spreading seems certain in the Woodlark Basin region, and a continent/island arc collision zone exists in northern New Guinea. An interpretation of the Cainozoic history of the New Guinea region is presented.

Earthquakes during June

DURING June there occurred at least nine world-shaking earthquakes and a great number of smaller ones. The greatest two of the month were that on June 28, which caused heavy casualties and severe property damage in and around Fukui, West Honshu, Japan (Nature, July 10, p. 57) and which gave ground amplitudes at Durham of 115µ, and that on June 30, which caused casualties and property damage on the island of Levkas and the nearby mainland of Greece, and gave ground amplitudes of 220µ at Kew. The other great shocks were on June 15 near the southern coast of Honshu, Japan ; on June 18 in the Solomon Islands region ; on June 21 in the Celebes Sea ; on June 27 (2) off the northern coast of Honduras and south of the Alaska Peninsula ; and on June 29 (2) in the Samoan Islands region and in Transcaucasia. An earthquake only slightly less intense occurred on June 13 from a focus the epicentre of which was near lat. 43°31‘N., long. 12° 8‘E. This caused some property damage and at least one death at San Sepolcro in the Italian Province of Arezzo. Also during the month there was a swarm of earthquakes in the Karlsruhe, Rasstat, Lauterbourg area. The swarm began on June 1 and lasted practically the whole month, the greatest shock of the series being felt on June 7 with scale VI to VII (some chimneys down) at Karlsruhe. The epicentre of this shock was near lat. 49°04‘N., long. 8°19‘E. some 9 km. north-west of Karlsruhe, and the depth of focus has been estimated at 20–30 km. The energy of the shocks of this swarm did not travel far, but was recorded by the seismographs at Strasbourg, Stuttgart and the Swiss observatories. Apart from the observatories mentioned above, reports for the month have also been received from the U.S. Coast and Geodetic Survey, Aberdeen, Beograd, Cleveland (Ohio), De Bilt, Toledo and Uccle.