3 NAVIGATION OVERVIEW AND POSITION INFORMATION



3.1 Navigation Overview for NeMO 2000 - Susan Merle, Bill Chadwick, Julia Getsiv, Lisa Crowder



For the NeMO 2000 Cruise we made use of the R/V Ron Brown 's extendable through hull transducer pole. While in Newport prior to the cruise, the NOAA range meter was mounted on the pole so it could be used for transponder calibrations. ROPOS also had a spare range meter that was mounted on the cage. The extendable through hull transducer pole method eliminated the need to use "El Guapo" for calibration of transponder nets. The bad micro-processor in the NOAA PS-8000 that was a problem last year was replaced prior to the 2000 cruise and worked well this year throughout the cruise.

As in previous years, all ROPOS dives were navigated using long-baseline transponder nets with the Seascape navigation software. The navigation computer had three main inputs into Seascape to aid in ROPOS navigation: P-code GPS from the R/V Ron Brown, ROPOS sensor data and the PS8000 data from the range meter. Customized output files were created to save additional ROV sensor information for Imagenex processing (such as depth, altimeter, gyro, pitch and roll).

Transponders were already in place for the South Cleft, ASHES and the North Rift Zone (NRZ) nets. Deployed in 1998, the expendable transponders should have five year lifetimes. The transponders for those three nets only needed to be enabled. A fourth net, at the Southern Pillow Anomaly at 45 52'N was added with three recoverable transponders.

One issue that was more problematic in 2000 than in the past was "cage-motor noise". When the cage motor was on navigation was sporadic, at best. When the cage motor was turned off nav improved dramatically. This year the ROPOS crew did not want to turn the cage motor off very often, as they were afraid they wouldn't be able to start it back up again because of other changes related to their new cable. There were also problems with deckset errors which made it necessary to quit out of nav and cycle the PS8000, usually resulting in good ranges when the program was restarted. For the last 3 years we have had a persistent problem with the RMS errors being inexplicably much higher (RMS=12-25) on the ROPOS fixes than on the cage fixes (RMS=1-2). The range legs to ROPOS are all consistently long, which is problematic because it causes fixes to jump large distances depending on which transponders are heard. The low cage RMS suggests the transponder calibration is fine, plus we have this problem in all our nets, and we have double checked all the transponder parameters. We do not know if this is a hardware problem (perhaps if the relay on ROPOS actually has a different turn around time than indicated, for example) or if it is a software problem somehow.

Navigation fixes are recorded in UTM x/y (meters) in the log files and were processed by Julia Getsiv using the IDL program navedit2 (written by Bill Chadwick). The processed navigation was brought into GMT (generic mapping tools) by Susan Merle for dive map production. The dive maps are a useful guide to determine navigation gaps, bad navigation, etc. When acoustic nav was not available GPS ship nav was used.

3.2 NeMO '00 Final Calibrated Transponder Positions



XP=Transponder Frequency

South Cleft Net

XP UTM X UTM Y Latitude Longitude Depth(m)

8.5 394569.87 4949335.07 44 41.37830 130 19.83128 1919.9

9.5 393718.81 4947296.1 44 40.26972 130 20.45012 1908.3

10.0 392492.04 4943450.03 44 38.18189 130 21.33007 1947.2

10.5 393070.28 4945529.36 44 39.30990 130 20.91876 1934.8

11.5 391107.96 49476546.57 4440.44089 130 22.43046 1919.4

12.5 391657.37 4941553.62 4437.15031 130 21.93730 2010.4



North Rift Net

XP UTM X UTM Y Latitude Longitude Depth (m)

9.5 420814.65 5098603.9 46 02.1857' 130 01.3988' 1433.9

10.5 422722.92 5097596.31 46 01.6548' 129 59.9096' 1395.43

8.0 420055.52 5095969.44 46 00.7580' 130 01.9608' 1377.93

7.5 422074.85 5094971.24 46 00.2330' 130 00.3862' 1294.46



ASHES Net

XP UTM X UTM Y Latitude Longitude Depth (m)

11.5 424283.25 5087181.51 45 56.0418' 129 58.6011' 1305.4

10.5 424221.58 5084426.79 45 54.5540' 129 58.6227' 1340.36

9.5 422490.35 5086188.55 45 55.4937' 129 59.9789' 1324.67

11.0 422556.72 5088014.47 45 56.4800' 129 59.9453' 1330.85



Southern Pillow Flow

XP UTM-X (m) UTM-Y (m) Latitude Longitude Depth (m)

10.0 421724.58 5081207.57 45 55.6778 130 0.5720 1476.74

8.5 423360.49 5079719.36 45 54.8853 129 59.2921 1548.25

12.5 421060.96 5079245.12 45 54.6137 130 1.06616 1508.08


3.3 Vent and Marker Location Table

Vents and Markers Area/Vent Longitude Latitude UTM X UTM Y Depth
Bag City Vent Mkr-36 nSRZ -129.98943 45.91617 423271 5085209 1534
Blue Nose Vent 98 lava flow -129.98370 45.94544 423755 5088451 1524
Bob Vent NRZ -130.01283 46.03892 421629.2 5098870.2 1590
Castle Vent 98 lava flow -129.97990 45.92613 424022.7 5086305.8 1520
Castle Mkr-N5(Flattop) Castle -129.97960 45.92610 424043 5086306 1516
Circ Vent 98 lava flow -129.98165 45.92592 423887 5086283
Cloud Vent 98 lava flow -129.98156 45.93335 423904 5087110 1524
Cloud Mkr-N4 Cloud -129.98167 45.93342 423896 5087119 1523
Cloud Mkr-N6/21 Cloud -129.98160 45.93340 423901.4 5087116 1524
Coquille Vent 98 lava flow -129.99306 45.91753 422991 5085365 1537
Crack Vent ASHES -130.01355 45.93330 421424 5087135 1547
Crevice SRZ -129.99040 45.91110 423175 5084648 1538
Dave's Vent ASHES -130.01377 45.93352 421408.3 5087158.6
Dying Vent 98 lava flow -129.99185 45.91685 423083.7 5085286.4
Easy Vent 98 lava flow -129.98472 45.94533 423676.5 5088443.2 1532
FeCity Vent nSRZ -129.98919 45.91754 423291 5085361 1535
Fe-Hyde Vent ASHES -130.01378 45.93298 421406 5087099.7
Gollum Vent ASHES -130.01358 45.93358 421422 5087166.1 1546
Hairdo Vent ASHES -130.01398 45.93350 421390.7 5087156.8 1546
Hell Vent ASHES -130.01423 45.93330 421372 5087135 1544
Hillock/Phoenix Vent ASHES -130.01398 45.93325 421390.9 5087130.4 1544
Inferno Vent ASHES -130.01390 45.93355 421397.2 5087162.2 1547
Joystick Vent Mkr-42 nSRZ -129.98856 45.91884 423341.5 5085505 1536
Magnesia Vent Mkr-67 98 lava flow -129.98493 45.94623 423660.7 5088544.7 1530
Marshmallow Vent ASHES -130.01362 45.93370 421420.4 5087179 1547
Medusa Vent ASHES -130.01393 45.93335 421394.7 5087141.1 1546
Milky Vent Mkr-N2 98 lava flow -129.98475 45.94514 423673 5088424 1527
Minisnow Vent Mkr-N9 98 lava flow -129.98422 45.94262 423711 5088141 1522
Mkr-I ASHES -130.01367 45.93370 421416 5087180
Mkr-108 Vent 98 lava flow -129.98303 45.92865 423784 5086589 1520
Mkr-113 Vent 98 lava flow -129.98817 45.92266 423377 5085929 1524
Mkr-2 ASHES -130.01397 45.93330 421392 5087136
Mkr-33 Vent 98 lava flow -129.98225 45.93327 423850.3 5087101.1 1524
Mkr-D ASHES -130.01393 45.93325 421399 5087129
Mkr-L ASHES -130.01432 45.93333 421365 5087140
Mkr-N1 98 lava flow -129.98408 45.93980 423718 5087828 1521
Mkr-N3 98 lava flow -129.98520 45.94380 423637 5088278
Mkr-N41 98 lava flow -129.98138 45.93622 423922.4 5087428.2 1520
Mkr-N44 98 lava flow -129.98483 45.93947 423658 5087792
Mkr-N7 98 lava flow -129.98190 45.93930 423886 5087774 1520
Mkr-65 near BagCity -129.98963 45.9160141 423255 5085192 1534
Mushroom Vent ASHES -130.01380 45.93360 421405.3 5087167.9 1548
Nascent Vent Mkr-M 98 lava flow -129.98160 45.93584 423905 5087387 1520
Old Flow Vent 98 lava flow -129.98170 45.93645 423897.5 5087454.7 1534
OldWorms Vent 98 lava flow -129.98331 45.94510 423785 5088418 1528
Ouzo Vent 98 lava flow -129.98468 45.94582 423679.6 5088496.8 1526
Oxide Vent 98 lava flow -129.98508 45.94545 423647.9 5088456.4 1543
Pillar Vent 98 lava flow -129.98542 45.92270 423591 5085929.1
Roof Vent 98 lava flow -129.98448 45.94250 423689.8 5088129.1 1523
ROPOS Vent ASHES -130.01405 45.93328 421386.1 5087134.1 1547
Snail Vent 98 lava flow -129.98188 45.93317 423878.6 5087089.7 1525
Snail Mkr-N8 Snail -129.98190 45.93320 423877 5087088 1523
Snow Vent 98 lava flow -129.98245 45.92712 423827 5086417
SnowBlower Vent 98 lava flow -129.98407 45.93987 423719 5087835 1521
SteveMound ASHES -130.01342 45.93325 4214348 5087128.6
Styx Vent ASHES -130.01370 45.93328 421412.2 5087132.2
ThePit Vent 98 lava flow -129.98408 45.93975 423718.2 5087823.2 1521
Tombstone Vent ASHES -130.01133 45.92948 421590 5086597
Tunnicliffe Vent ASHES -130.01582 45.93367 421248.7 5087178 1544
VirgDaut Vent ASHES -130.01340 45.93375 421436 5087184 1547
Virgin Vent ASHES -130.01348 45.93365 421430 5087174 1547
White Vent ASHES -130.01363 45.93373 421419 5087182.9
91Vent NRZ -130.01242 46.03860 421661.4 5098834.3
Shepherd Vent CASM -130.02668 45.98990 420486.4 5093373.6 1583
SoCasm Vent CASM -130.02625 45.98870 420518.6 5093304.6 1583
AX-BM63 Cald center -130.01017 45.95522 421717 5089568 1530
AX-BM1 Magnesia -129.98490 45.94622 423663 5088544 1524
AX-BM5 Mkr-33 -129.98242 45.93335 423838 5087111 1523
AX-BM4 Bag City -129.98963 45.91601 423255 5085192 1534
AX-BM66 South Anom -130.00371 45.86315 422089 5079332 1723
BPR Caldera center -130.01017 45.95522 421717 5089568 1530




3.4 Pressure Benchmark Locations at Axial Volcano (deployed during NeMO 2000 cruise - Dives R546 and R548)

Name Location UTM X UTM Y Lat Long Depth (m) Radial distance (m) from caldera center Site Description
AX-BM63 Caldera center 421717 5089568 45.95522 -130.01017 ~1530 0 Located right next to NeMO2000 BPR mooring, perhaps 50 m north of Paw Flow (flat ropy sheets) in low lobates. Marker 63 is attached to the benchmark.
AX-BM1 Magnesia 423663 5088544 45.94622 -129.98490 1524 2199 Right next to Marker 67 (Magnesia), which is on uncollapsed roof surrounded by collapse. No marker on benchmark.
AX-BM5 Marker 33 423838 5087111 45.93335 -129.98242 1523 3245 15 meters NW of Marker 33 (visible). No marker on benchmark.
AX-BM4 Bag City 423255 5085192 45.91601 -129.98963 1534 4638 17 m south and 16 m west of Bag City (Marker 36). Marker 65 is located at the benchmark.
AX-BM66 South Anomaly 422089 5079332 45.86315 -130.00371 1723 10243 Located on the western lip of the 1998 eruptive fissure where the new lava is 1-2 m below the rim. In very flat sheet flow. Marker 66 is attached to benchmark.