Map of Mona Island. Island is approx. circular with diameter ~10km. There are cliffs all along northern and eastern side. Sea cliffs become ridges to west and south west, with beaches below the ridge. Interior of the island is very very flat. There is an existing seismic installtion in a lighthouse near the peak contour about 1km south of Cabo Noroeste (lighthouse is not marked on the map). At this site, sensors are placed on the groundin a small building with no vault. The purpose of the trip was to scout for locations to build a seismic vault with improved conditions, and good access for proposed satellite communications. Current site has very limited access, it will be exceedingly difficult to bring equipment and materials to create vault without chopper support. Sites near the port at Sardinera can be accessed by boat. Helicopter landed on a strip of grass at Punta Arenas in SW of island. Sites scouted on this visit are: 1. solar panel field on ridge just above (east of) the Sardinera campground 2. cave on ridge just above (east of) the Sardinera campground 3. airstrip All these sites have improved access. With all these locations, there is likely to be significant difficulty with gaining permit to excavate on island.
SE tip of Mona, incl. lighthouse, view from appraoch to island from the northwest
View looking south from north of mona. Most of island surrounded by these severe cliffs. Plateau above is extremly flat. Current location of station is beside a small lighthouse set back about 1km from shore.
Typical view of interior of Mona. short but thick scrubland, very flat, almost no paths, not even rudimentary ones.
Pier on Mona beside main campground (Sardineria) where tide gauge will be installed
View of campground from pier
Option A : airfield in SW of island. View from the east. Strip is 0.5miles long. Best location would be at the east end (aircraft parks on west end, most traffic towards beaches at top of photo), 2nd alternative, if impossible to get permissions to place satellite antenna on runway end environs, is the excess aircraft parking zone in middle right of runway, or small access road beside it. Note, any location on field is probably optimal location on island, as 1. brush is always cleared for satellite communications, 2. access is excellent 3. only ~7 flights / week, very quiet site 4. about as far from shore (~200m) as any site with such good access. Wind and shore noise appears relatively lower than other sites scouted. Drawbacks: 1. still close to shore 2. rock underfoot, but potential to dig to depth is more realistic as easy access for on-site backhoe or imported jackhammer. Even so, no site on island with more than a few cm of topsoil was known to persons in charge on the island. 3. potential extension to airfield in future, though this appears to be unlikely.
Airfield : close up of secondary apron in center of runway. Access road from apron leading to bottom right corner of photo is obscured by trees. Note exposed rock on runway.
Airfield viewed from SW. Ridge is beginning to rise is very top left corner of photo. the beach is quite nice!
Access road from main camp site and dock to airport.
Option B : Solar panel field on ridge just above the main campground at Sardineria
view of solar panel field from path leading towards interior
View from near solar panel farm and cave - solar farm set back about 15m from this site, cave about 10m, so both sites are very close to ridge edge.
Option C : cave near solar panel farm. Certainly this site is quieter than the solar farm, but: 1. permissions to get a site in here - our contact on the island did not think there would be a problem, but myself and Juan Lugo were not so sure. 2. water. Its damp in here. 3. stability of cave system (collapse!) in the long term. 4. very likely rock falls and other local noise in the event of even moderate ground motions.
view from inside cave.
ledge above cave, potential site for location of datalogger and satellite if this location selected.
Desecheo Island, viewed from the South, on the way