U.S. Geological Survey Open File Report OF-93-7

Ocean Bottom Seismometers Operation during the Seismic Survey 

of Lake Baikal, Siberia, Autumn 1992.

Uri S. ten Brink 

U.S. Geological Survey, Woods Hole, MA 02543, USA.

Alik Badardinov

Limnological Institute of the Siberian Branch of the 

Russian Academy of Science, Listvyanka, Russia.

Gregory K. Miller 

U.S. Geological Survey, Woods Hole, MA 02543, USA.

Dwight F. Coleman 

U.S. Geological Survey, Woods Hole, MA 02543, USA.

December 29,1992
SUMMARY

A seismic survey of Lake Baikal, Siberia, was jointly undertaken by U.S. and Russian 

scientists during August-September of 1992. The experiment was carried out by two ships, the R/V 

Balkhash, which was equipped with airguns and a multichannel seismic streamer, and the R/V 

Titov, which was used for the deployment of Ocean Bottom Seismometers. The experiment was 

funded by the U.S. Geological Survey, the U.S. National Science Foundation, and the Russian 

Academy of Science. This report summarizes the operation of Ocean Bottom Seismometers (OBS) 

aboard the R/V Titov. A companion report by Klitgord et al. (1993) summarizes the multichannel 

seismic program and the operation aboard the R/V Balkhash, and a third report by Nichols et al. 

(1993) describes the logistical and technical aspects of the entire seismic program.

The objective of the Ocean Bottom Seismometers (OBS) program was to determine the 

velocity structure of the sediments, crust, and uppermost mantle under the Baikal rift in order to 

better understand the tectonic evolution of the rift. To this end, a 240-km-long wide-angle reflection 

and refraction line was collected with 5 OBSs along the axis of the Central Basin using two large (60 

liter each) airguns as a sound source. The northern 140 km portion of this line was repeated with 6 

OBSs recording a tuned 10-gun array with a total volume of 27.3 liter. Another 160-km-long wideangle reflection and refraction line along the southern part of the Northern Basin was recorded with 

5 OBSs and shot with the two large airguns . A 70 km long tie-line between the Northern Basin and 

Central Basin lines was shot across the Academician Ridge with the tuned airgun array and was 

recorded with 4 OBSs. Multichannel seismic (MCS) reflection lines were collected by the R/V 

Balkhash along all the OBS lines with the exception of the southern 130-km-portion of the Central 

Basin line which was collected during the 1989 MCS cruise. Many of the OBSs were deployed at the 

intersection of two orthogonal MCS lines in order to better constrain the shallow 3-D structure. A 

total of 34 successful deployments and retrievals of USGS OBS, the largest to date in a single survey, 

were carried out despite the crowded conditions and inadequate facilities on the R/V Titov. Data 

were recorded in 20 of these deployments. None of the instruments were lost. Initial record sections 

show good signal to noise ratio on all OBS channels in all the lines persisting to the maximum shotreceiver offsets.

SCIENTIFIC OBJECTIVES

The Baikal rift system is a large and active continental rift, stretching over 1800 km along 

the boundary between the stable continental platform of Siberia and the continental fragments of 

southeast Asia. The 600 km long Lake Baikal, which lies at the center of this rift system is divided

Baikal 92 OBS 2 OF-93-7
80°N 80°E 180°E 80°N

60°N

RUSSIA

160°

120°E

Figure la. Location of Lake Baikal.
52030'N

52«15'N

105°30'E 106°E 107-E

Mercator Projection 

Latitude of true scale: 53°

20

108°E

20 40

109*E

'30'N

 52°30'N

109°30'E

52°15'N

60 80 100 KILOMETERS

Figure Ib. Location of OBS stations and OBS lines. Circles - Deployment 1 and 

2, Crosses - Deployment 3, Stars - Deployment 4, Diamonds - Deployment 5. 

Al, A2, A3, Bl, Cl, C4, C9 - Instrument names.
into three bathymetric and tectonic basins, the Southern, Central, and Northern Basins. The Central 

Basin is the deepest basin reaching more than 16CX) m below lake level and having up to 7.5 km of 

sediments. The scientific objectives of the OBS experiment were:

 To determine the depth to Moho under the Central and Northern Basin in order to resolve whether 

Moho is elevated under the rift.

 To determine P and S wave velocities for the lower crust and upper mantle in order to identify the 

role of magma upwelling under the rift.

 To compare among the crustal velocity structures of the Central and Northern Basins/ the 

Academician Ridge, and published velocity structure outside the rift in order to understand the 

contribution of the preexisting crustal rheology to the development of the rift.

 To determine the velocity of the deep (> 5 km) sedimentary section observed on multichannel 

seismic records in order to assist in their geological interpretation.

OPERATIONAL OBJECTIVES

 To test two new OBS spheres and their electronics.

 To test several recent improvements to the OBSs including hydrophone connectors, variable 

sampling rate, backup power supply for release, and time calibration by GPS.

 To make multiple deployments with a minimum turn around time off a modest size ship.

 To test the release and natural buoyancy of the OBS in a fresh water lake.

 To carry out the entire operation off a foreign ship with foreign power supply and foreign radio 

communication.

 To maintain good communication with the personnel on board the R/V Balkhash at all times in 

order to maximize the number of deployments and minimize the effect on the collection of 

multichannel seismic reflection data.

Baikal 92 OBS 3 OF-93-7
THE USGS OCEAN BOTTOM SEISMOMETERS

The Ocean Bottom Seismometer (OBS) is a self-contained data-acquisition system that is 

deployed on the ocean floor to record wide-offset seismic data on a 200 Megabyte disk. The US 

Geological Survey OBS has been designed as a continuous recording system setup to acquire signals 

from one vertical 4.5 Hertz geophone, two orthogonal horizontal 4.5 Hertz geophones, and one 

hydrophone. The software controlling the system can select any combination of these four channels to 

sample at 200 samples/second, providing a record time of 36 hours for all four channels. Once during 

each acquisition of data into the memory buffer (1,015,808 bytes), the system will record the time of 

the sample. The time and the data pointer for that time are recorded into a header mat gets 

recorded with each memory buffer of data. There are eight OBS's. Four are housed in small (51 cm in 

diameter) spheres rated for a depth of up to 500 meters, and the other four OBS's are housed in large 

(61 cm in diameter) spheres rated to 5,000 meters. Each OBS is powered using 72 alkaline batteries 

which will run all of the systems for seven days.

The OBS's record data continuously and have time-of-day marks in the data as the only 

reference to external events. To provide the highest possible accuracy, time is recorded to the nearest 

millisecond. Each OBS uses an oven-controlled oscillator as a stable clock reference, for which the 

drift in time can be as little as 0.5 milliseconds/day. This accuracy requires several days of careful 

calibration and the use of a rubidium (Rb) standard as a reference for the oscillators. All eight OBS 

data loggers are continuously powered using a 24 volt DC power supply to keep the oscillators at a 

constant temperature. Prior to each deployment, the frequency of each oscillator is checked and, if 

necessary, recalibrated. The time-of-day is set via software in each logger using the minute pulse of 

the GPS satellite clock as a starting trigger. When locked on a satellite, the time is accurate to 

within 100 nanoseconds, and the Rb standard can used to maintain an accurate time when satellite 

coverage is not adequate. The offset from GPS time is determined by comparing the second pulse of the 

data logger with the second pulse of the GPS clock. After each deployment, the offset is measured 

again to determine the total drift.

The dataloggers in each OBS use a 200 Megabyte hard disk to store the acquired data. The 

data must be transferred to another storage media each time an OBS is retrieved. A 386 PC with 2.2 

gigabytes of hard disk and an exabyte tape drive is used to archive the data. Data are downloaded 

from the data logger onto the hard disk of the PC. The quality of the data is checked using two 

programs. One program reads, displays, and checks the header information of each data record. The 

program will report any errors found. The second program graphically displays the sensor data for

Baikal 92 OBS 4 OF-93-7
all four channels. Once all of the OBS's have been downloaded, the data files are written to Exabyte 

(8 mm) tape for permanent storage.

Deployment and recovery are simple operations designed to work on a variety of different 

vessels. The OBS's are programmed, sealed, and stored on deck prior to deployment. When at the 

point of deployment, the release is tested a final time, and the OBS is then attached to its anchor. 

The preferred method of deployment uses a winch to lift the OBS and anchor and an A-frame to move 

the assembly outboard of the ship. The OBS is then lowered to the water surface where a simple 

rope loop and metal pin is used to release the OBS into the water and freefall to the bottom. An 

acoustic release is used to free the OBS from its anchor. Once released, the OBS rises to the surface at 

a rate of 1 meter/second. At the surface, two externally mounted strobes will flash to aid in sporting 

the floating OBS. The OBS is attached to the lifting line using a snap hook mounted on a pole, and/ 

once the OBS is lifted back aboard, the release is recocked to turn off the strobes. The large OBS and 

anchor weigh 250 Ibs. in air, so the requirements for lifting are not much. A block and tackle are often 

used (as in this experiment) when no winch is available.

NARRATIVE 

Pre-deployment

All of the OBS equipment plus 40 anchors and 3200 alkaline batteries were packed into a 

standard 20 foot shipping container and sent out in early April as part of a 3-container shipment to 

Lake Baikal. The equipment arrived in Listvyanka in mid-July. The OBS technician and a 

translator, arrived in early August to nmobilize the OBS and to assist in mobilizing the 

multichannel/shooting ship (the R/V Balkash). Prior to embarkation a plywood shack was 

constructed on board the R/V Titov to serve as the OBS laboratory (see Appendix 6). The experiment 

took place during the short Siberian automn. The weather throughout the experiment was mild/ 

with the exception of one severe snow storm on September 5-7, and continued rough seas and cold 

weather in the following week. Air temperature varied between 0°-15° C, and the water 

temperature was estimated at 5°-10°C wind speed was generally 5-15 m/s and waves 0.5-1.5 m high. 

The R/V Titov left the pier of the Limnological Institute in Listvyanka on August 30 at 14:30 local 

time (9 hours ahead of GMT) following loading of the scientific gear on board that morning. 

Although the first OBS deployment was scheduled 5 days later, an early departure was necessary, to 

avoid vandalism in port and to complete sea-going preparation of the ship and its crew. The Titov 

initially headed south to Baikalsk, on the Trans-Sibirian railroad, to stock on food, but because the 

late departure meant the supplier will close before arriving at Baikalsk, the R/V Titov changed 

directions and headed north toward the Selenga delta to rendezvous with the R/V Balkhash. The

Baikal 92 OBS 5 OF-93-7
Listvyanka shore station had no radio communication with the Balkhash after she left port on 

August 25, so messages could not be relayed to the scientists on board. The R/V Titov arrived to 

within VHP radio contact and we communicated successfully with the Balkhash. Afterwards the 

Titov headed back south to the vicinity of Baikalsk and anchored in shallow waters. The morning of 

August 31 was spent shopping and in the afternoon we headed north to Buckhta Pesjanaya (Sandy 

Bay) and tied to the pier. A test was made to test the buoyancy of the OBSs in fresh water and verify 

that the OBSs float above sea surface and could be detected. September 1 was spent at Pesjanaya Bay. 

During these three days the OBS lab was outfitted and all OBSs were tested and programmed for the 

first deployment. A faulty transducer was found and could not be repaired. For lack of spare parts 

only 7 out of 8 OBSs could be deployed throughout the experiment. Parts were exchanged so that a 

small sphere (OBS C3) would not be deployed. On September 2, we sailed further north toward the 

northern end of OBS line 1 stopping on the way to climb to Ulan-Ur to examine an unusual assemblage 

of carbonatite, garnet peridotite, amazonite, etc. all exposed within a small area. The night was 

spent at anchor in Barguzin Bay at the northern end of OBS line 1.

Deployment 1 (Central Basin)

At 07:15 local time (hereafter LT) on September 3 we deployed the first OBS C4 along line 

OBS1 (Fig. 1). Deployment of all OBSs was successful and uneventful. The good weather during the 

previous days turned into high wind and waves as we deployed the last two OBSs (Cl and C9, Fig. 1). 

Deployment was completed at 20:23 and the Titov headed back to Listvyanka and arrived there on 

9/4 at 02:30 LT. The R/V Balkhash arrived at Listvyanka on the evening 9/2 to allow for personal 

errands of the ship's chief engineer and was scheduled to leave the next evening and start shooting on 

9/4 at 12:00 LT. To our surprise, the captain of the Balkhash refused to leave port, citing a bad 

weather forecast. The R/V Titov left Listvyanka on 9/4 at 16:00 LT to refuel in Port Baikal. The sea 

was fairly calm. At 18:00 LT the Titov returned to Listvyanka and I walked over to the Balkhash in 

another failed attempt to bring the Russian chief scientist on board, to convince the captain to 

immediately start shooting the OBS line. At 19:00 LT the Titov left for Pesjanaya Bay. On the 

afternoon of the next day (9/5) the weather deteriorated and rain and sleet began to fall. 

Nevertheless, an attempt was made at 17:00 LT to recover the southernmost OBS, but as the wind and 

wave directions were perpendicular to one another, it was impossible for the Titov to keep station. 

The Titov returned to Pesjanaya Bay at 21:00 LT where she was well protected from the weather. 

Only during 9/6 did the wind reach gale storm. Wind was blowing first from the northwest and later 

from the south and raised columns of water. OBS retreival started on 9/7 10:45 LT when the weather 

improved some, although it was still "too severe" for the much larger Balkhash to work. All 7 OBSs 

were collected by Sept.8 04:00 LT. They all responded immediately to the release command and had

Baikal 92 OBS 6 OF-93-7
recorded for the entire 36 hours for which they were programmed. This deployment had no data 

because the Balkhash had not shot the line during the recording window.

Deployment 2 (Central Basin)

At the northern end of the line we turned to redeploy the OBS along the same line (OBS1, 

Fig. 1) starting at 05:00 LT. The retrieved OBSs were programed and prepared between stations. 

Weather was still fairly poor. The release mechanism of small sphere OBS Cl malfunctioned and it 

was not deployed. We finished the second deployment on 9/8 19:30 LT having deployed only 6 OBSs 

and pulled into Pesjanaya Bay. The Balkhash started shooting from southern end of line at 21:00 LT 

at a speed of 4 knots. It reached the northern end of the line on 9/10 03:00 LT and turned around and 

shot back for the remaining 2 hours of OBS recording. On September 9, while the Balkhash was 

shooting, the Titov sailed to the village of Galauchnaya (3 hours south of Pesjanaya Bay) in an 

unsuccessful search for food. In the meantime the release mechanism was repaired and OBS Cl was 

deployed at 9/9 17:11 LT and recorded the last 15 hours of the shooting. At 18:15 LT Titov 

rendezvoused with R/V Vereschagin off Buguldega to acoustically release a sediment trap for E. 

Karabanov. After successful release the Titov refueled from the R/V Vereschagin. On 9/10 at 09:20 

LT we left Pesjanaya Bay to retrieve the OBSs on line 1. OBS Bl off Olkhon channel was found to 

have bad gain ranging and the data were rendered useless. OBS Al would not release. The site was 

abandoned after 21/2 hours of attempts when the R/V Balkhash approached the site as she 

collected MCS line 92-38. We proceeded to retrieve the remaining two OBS. The tattletale on the 

northernmost OBS (C4) did not record any data. We finished retrieving OBS C4 on 9/11 03:04 LT and 

immediately returned to the site of OBS Al. After another hour, the OBS finally released from its 

anchor and was pulled on board at 09:24 LT. The sea at this time was rough and the R/V Titov found 

shelter on the leeward side of Olkhon Island at the foot of Mt. Burkhan. On 9/12 at 08:00 LT we 

attempted to start deployment of OBS Line 2 (along line 92-46 across Academician Ridge) and Line 3 

(line 92-15 along Academician Ridge) but rough seas forced us after less than an hour to return to 

sheltered water. The R/V Balkhash was collecting MCS data and changed the order of the lines to 

be shot to allow us time to deploy. At 10:30 LT we sailed to the village of MRS at the tip of Olkhon 

peninsula being protected from the northwesterly wind by the southeastern shore of Olkhon Island. A 

member of the scientific expedition, Dwight Coleman, was transferred there to a fast boat heading 

for Irkutsk for an early return to the U.S. The Titov left MRS at 16:30 LT toward Khushir where 

bread, meat, and vegetables were purchased.

Deployment 3 (Academician Ridge)

After leaving Khushir we headed north to start the third deployment along OBS lines 2 and 

3 (Fig. 1). At 23:11 LT we deployed the first OBS (Bl) off the tip of Olkhon Island. By that time the

Baikal 92 OBS 7 OF-93-7
sea was calm. Deployment of the 7 OBSs along Line 2 (Cl, Al, A2, and A3) and Line 3 (C4 and C9) 

continued throughout the night and ended at 9/13 08:55 LT off Ushkany Island. From there the Titov 

headed to Barguzin Bay and anchored offshore Svyatnoy Nos peninsula for a night of fishing for the 

crew. Balkhash started shooting line 92-46 at 17:00 LT with the 10-gun array every 24 seconds, but by 

the time she approached the start of line 92-15 (early morning of 9/14) the sea became rough and the 

captain of the Balkhash ordered the streamer and guns to be pulled on board. The Titov left Barguzin 

Bay at 08:00 LT and retrieved OBS Cl at the southern end of line 92-15 by 09:02 LT. After rough 3 

hours of rough passage across the lake, the R/V Titov rendezvoused with the R/V Balkhash in the 

sheltered water off Olkhon Island (under Mt. Burkhan). Attempts were made during the afternoon 

and evening to convince the Russian chief scientist to start shooting Line 3 before the recording time is 

over at 10:00 LT the next day. Although the sea was calm, the chief scientist did not order his crew to 

deploy the guns citing that he already promised them the night off. The R/V Titov left the 

sheltered water at 9/15 06:00 LT to retrieve all remaining OBSs. Retrieval was completed at 20:18 LT 

and all instruments were found to have recorded data during the shooting of Line 2. The lengthy 

retrieval was due to the circuitous route that the captain took in order not to be caught in potentially 

bad weather in the middle of the lake. But by the time retrieval was completed the sea was calm. 

The Titov was anchored for the night off Zunduk in Maloy More. In summary, off 7 OBS locations on 

Lines 2 and 3, data were only recorded for shots along Line 2 (4 instruments on line and 3 instruments 

off line). In addition, the southeastern 14 km of Line 1 were not shot for unknown reason.

Deployment 4 (Northern Basin)

The fourth deployment (Line OBS4) took place in the northern basin and started on 9/16 at 

09:04 LT off Zama (OBS C4, Fig. 1). The deployment was interrupted between 10:00 LT and 10:45 LT 

the Titov for rendezvous with the supply boat Papanin which was on its way to bring food to the 

Balkhash. Deployment was resumed and successfully completed at 19:56 LT off the mouth of Bolshoy 

River (OBS Cl). The night was spent being anchored near shore by the end of the line. Earlier in the 

day the R/V Balkhash completed the MCS shooting of this line (MCS 92-17) with the 10-gun array 

and changed to the two large 60 liter guns. At 9/17 00:00 LT, Balkhash started shooting at 4 knots 

towing the streamer behind. Shooting was completed at 9/17 21:45 LT. The Titov spent 9/17 tied to 

the pier at Davsha, near the northern end of the line waiting for an agreed upon radio communication 

from the Balkhash to announce that the line was completed. Since there was no communication from 

the Balkhash, and scientists on board the Balkhash gave different shooting speed (4 and 3.25 knots 

respectively) we waited till 9/18 08:00 LT to start retrieving. Our request was to shoot at 3.25 knots to 

achieve a 200 m spacing between shot points. However, the Balkhash opted to record the shots of 

the big guns using the multichannel streamer, requiring that the line be shot at 4 knots to maintain 

streamer buoyancy. Communication with Balkhash was established at 10:00 LT when the Balkhash

Baikal 92 OBS 8 OF-93-7
requested the Titov to buy cigarettes for its crew, who were threatening to quit. This was unfortunate 

since the Russian chief scientist released the supply boat that was assigned to him only a day 

earlier, and since the Titov had just left Davsha where cigarettes could have been cheaply 

purchased. The retrieval of all OBSs went smoothly, but two OBSs were found not to have recorded 

data. The oscillator on OBS Cl was detached from the tattletale, probably during deployment. The 

program on OBS C9 crashed on start-up and never started recording. This OBS had the problem of not 

transmitting response signals during a pre-deployment test on board but was deployed since the 

release mechanism functioned. It is hypothesized that both problems were due to a grounding 

problem. The retrieval of all OBS was completed on 9/18 20:27 LT and the Titov anchored for the 

night at Zunduk. On the morning of 9/19 the Titov went to Khushir to buy cigarettes for the 

Balkhash and try to refuel. However, cigarettes were expensive and a hose could not be found to 

pump fuel from an adjacent ship.

Deployment 5 (Central Basin)

Continuous, but unsuccessful attempts were made during the 9/19 to contact the Balkhash on 

the HF radio to find the start time for shooting the northern end of OBS linel (named OBS1A along 

line 92-13). The Titov could not afford to approach the Balkhash in order to establish VHP radio 

communication because of lack of fuel. Decision was made to wait in the channel separating Olkhon 

Island and Olkhon peninsula ("Olkhon Gate") and start deploying at midnight for an anticipated 

start of shooting at 9/21 10:00 LT. The OBSs had already been programmed to start recording at that 

time but at 19:00 LT we received a weather forecast predicting a storm overnight. We gambled and 

aborted deployment and reprogrammed the OBS to start recording 24 hours later. The Titov also 

moved to the sheltered water off the northern end of Olkhon Island in the hope of getting within 

VHP range from the Balkhash. Attempts to communicate with the Balkhash continued throughout 

the night and early morning of 9/20 and finally by 08:00 LT, the Balkhash came on the air and 

informed that indeed as of 03:00 LT the streamer and gun were ordered by the Captain to be pulled in 

because of bad weather. By midday the sea calmed and the weather was fine. Unable again to 

communicate with the Balkhash, a decision was made to reprogram the OBS for the earliest possible 

recording time, 9/21 03:00 LT. The R/V Vereschagin came alongside in the sheltered water at 14:00 

LT, supplied the Titov with 2 tons of diesel oil, and delivered a telex. At 15:10 LT the Titov started 

toward the southernmost OBS station. Communication was finally established at 16:00 LT at which 

we learned that the captain of the Balkhash left for the day to buy cigarettes and that the 

Balkhash will start shooting at or after 9/21 03:00 LT. Deployment of six OBS proceeded smoothly 

and ended at 9/21 02:15 LT in Barguzin Bay. The Balkhash started shooting the line south from 

Barguzin Bay at about 04:40. Shooting speed was 3.75 knots with a shot every 27 sec. to ensure that 

first arrivals from 130 km away are not truncated. Shooting ended at 9/21 23:30 LT. The Titov spent

Baikal 92 OBS 9 OF-93-7
the night anchored off Svyatoy Nos and spent the day tied to the pier in Ust Barguzin. The 

following night was spent again fishing off Svyatoy Nos. At 9/22 06:11 LT the Titov arrived at the 

northernmost OBS station, Cl, in Barguzin Bay and 1C) minutes later the OBS was on board. The 

second OBS was released and retrieval went smoothly. The third OBS, A2, was released without a 

problem, but could not be found on the surface. After comparing notes it was found that the captain 

wrote down the wrong coordinates during deployment and navigated the ship back to these erroneous 

coordinates. The Titov sailed to the correct location, 3.7 km to the north, and the OBS was found and 

retrieved. The release of the fourth OBS was uneventful, but the fifth OBS, Al, which was at depth 

of 1595 m did not release the anchor. Instead of the expected sequence of release sounds (pings) there 

were random pings, due probably to multiple reflections of the transmitted signal. After a 1.5 hour 

long attempt the entire length of the transducer cable (30-40 feet) was lowered and the anchor 

released immediately. Since the bathymetry is flat, it is hypothesized that the the multiples 

reflect off the thermocline or a more shallow boundary within the water. A similar problem was 

encountered in the release attempt of the last OBS, A3, so the transducer was lowered to the 

maximum cable length and the OBS released immediately and retrieved at 18:37 LT. The Titov then 

headed to Listvyanka as the main generator on the ship no longer functioned due to a broken lever 

arm. The scientists on the Balkhash requested another deployment across Posol'sky Bank but the 

captain of the Titov refused to continue working with only one generator. With one (small) generator 

the power supply to the GPS clock and other electronic equipment became unstable. A sixth 

deployment was therefore cancelled. Titov arrived at Listvyanka at 9/23 05:45 LT, and 

demobilization of the equipment on board was completed 10 hours later.

RECOMMENDATIONS

The biggest problems revolved around the acoustic release equipment. The power supplies for 

the deck electronics need to be replaced with units that are not as susceptible to noise as the existing 

units. Five of the eight OBS's use the newer releases electronics, while the remaining three still use 

the older electronics. Since there is no compatibility between the two systems, all of the OBS's need 

to be converted to use the newer releases. Boards also need to be purchased to provide spares. 

Currently, a release failure means that the OBS can no longer be used.

Another problem highlighted in this experiment is the limited use for the small OBS 

spheres. These OBSs can be deployed in water depth less than 500 m. Water depth in the lake was 

almost everywhere larger than 500 m. In addition, OBSs deployed at water depth shallower than 

100 m tend to suffer from a high noise level due probably to wave action. Therefore, there is a limited 

use for OBSs in wide shallow shelves. The depth limitation meant that the OBSs could not be

Baikal 92 OBS 10 OF-93-7
deployed at even intervals, which adversely affects the interpretation of the data. It is 

recommended that the small spheres be replaced with larger ones capable of deployment to 5000 m.

The data record time of 36 hours has proven to be only marginal in these type of operations. 

Using a sampling rate of 100 samples/second, instead of the current 200 samples/second, would 

increase the record time to 72 hours. Increasing the hard disk from 200 to 500 Megabytes should also 

be explored. There is no temperature data on these drives yet, but the new drive could double the 

record time while preserving the original sample rate.

Bad weather during and after the first deployment prevented any retreival of the OBSs for 5 

days. The current battery life will maintain operations for approximately 7 days (although this has 

to be unequivocally tested in the lab). Using small boats that do not have the rough weather 

capability makes the seven day limit a poor safety margin. This is especially true in operations 

where one day is required to deploy, 2 days for shooting the line, and another day for recovery. A 3 

day weather delay could be disastrous. The safety margin will also be inadequate if the recording 

window is doubled or tripled in the near future. The solution that should be explored to solve this 

problem is to use a low-power temperature-compensated oscillator rather than the current highpower oven-controlled oscillator. The oscillator draws by far more power than any other component 

in the OBS. The change in oscillator would increase the deployment time by a factor of three. In 

operations where the oven-controlled oscilators are required, lithium batteries should be used to 

increase the deployment by a factor of two.

The OBS operations in Siberia were successful despite the many problems in the release and 

recording equipment. The communication problem was severe and should, in the future, warrant the 

expense of renting satellite communication units. The HF radios used on Russian vessels are 

inadequate for reliable communications, and the lake was too large for line-of-sight radios such as 

VHP.

This operation illustrates the problems of using the OBS's in a ship-of-opportunity, 

multiship operations. There is an increasing need for portability and a decreasing availability of 

facilities for OBS operations. More spares are needed to quickly repair OBS's, since there is usually 

not enough time to troubleshoot problems between lines. Longer recording times for the OBS's are 

needed to ease some of the problems in communications. The larger the time window available for 

shooting, the more adjustments that can be tolerated in the shooting ship's schedule. A small 

shipping container should be setup to act as a lab to use in situations where lab space is not available. 

The plywood lab used on the Titov was too small and unsafe.

Baikal 92 OBS 11 OF-93-7
REFERENCES

Klitgord, K.D., Golmshtok, A.J., Scholz, C.A., Akentiev, L., Nichols, D., Schneider, C., McGill, 

J., Foster, D., and Unger, D., 1993, Seismic survey of Lake Baikal, Siberia cruise report: RV 

Balkhash 25 August to 25 September, U.S. Geological Survey Open File Report OF93-xx.

Nichols, D.R., Miller, G., and Akentiev, L., 1993, Seismic survey of Lake Baikal, Siberia: 

Operational technical summary for the RV Balkhash and RV Titov 15 August to 30 

September 1992, U.S. Geological Survey Open File Report OF92-693.

Baikal 92 OBS 12 OF-93-7
APPENDIX 1

Crew list R/V Titov

Uri S. ten Brink - USGS, Scientist

Gregory K. Miller - USGS, OBS technician

Alik Badardinov - Limnological Institute, Listvyanka, Liason

Marc Behrendt - Duke University, Translator

Dwight F. Coleman - USGS, assistant (until 9/12/92)

Alexander Sakhalov - Captain

Victor Platonov - Chief engineer

Sergey - Mate

Vasili - Oiler

Valera - Radio man and deck hand

Valera - Deck hand

Alexandra Alexandrovna - Cook

Baikal 92 OBS 13 OF-93-7
APPENDIX 2

Instrument location (see map)

Deployment 1

Locations were similar (within ± 50 m) to these of Deployment 2. The line was not shot.

Deployment 2 - Line OBS1 - Central Basin

OBS I.D. Lat/Long

at deployment at retrieval

Water depth (m) Comments 

denlov retrieve man ranging

OBSC4

OBS A3

OBSA1

OBSB1

OBSA2

OBSC1

OBSC9

Deployment 3

OBSB1

OBSC1

OBSA1

OBSA2

OBS A3

OBSC4

OBS C9

53 30 57 

108 45 25

53 19 36 

108 16 48

53 07 33 

107 46 42

52 52 20 

107 09 08

52 37 57 

106 34 46

52 26 22 

10607 18

52 24 36 

10603 10

53 30 57 

108 45 17

53 19 34 

108 16 48

530731 

107 46 47

52 52 18 

107 09 07

52 37 55 

106 34 49

52 26 21 

106 07 19

52 24 38 

10603 12

108

1655

1713

1497

1131

322

456

112

1664

1713

1496

1143

322

455

-

1542 -

1614 -

1423 1445

1028 -

-300 -

-440 -

Failed to record data

Failed to record data

Started recording at 

9/9 09:00 GMT

No hydrophone data

- Lines OBS2 & OBS3 - Across and along Academician Ridge

53 21 52 

107 52 03

53 12 20 

108 25 26

53 21 28 

108 14 49

53 30 28 

108 04 24

53 42 00 

107 50 53

53 43 01 

108 21 46

53 51 59

53 21 50 

107 52 00

53 10 19 

108 25 26

53 21 30 

108 14 56

53 30 29 

108 04 24

53 41 59 

107 50 53

53 43 00 

108 21 46

53 52 05

716

143

1710

711

732

365

174

714

149

1710

711

730

364

188

+700 -

+ 100 -

1618 -

-580 -

-660 -

-300

. 250 m before target 1

Baikal 92 OBS 14 OF-93-7
Deployment

OBSC4

OBSC9

OBSA1

OBSA2

OBSA3

OBSB1

OBSC1

Deployment

OBSA3

OBSA1

OBSB1

OBSA2

OBSC4

OBSC1

108 34 55

4-LineOBS4-

533006 

107 35 56

53 33 21 

107 42 20

534422 

108 03 33

5355 11 

108 24 34

54 07 20 

108 48 19

54 19 25 

109 12 24

54 25 07 

109 24 21

108 35 05

Northern Basin

53 30 02 

107 35 56

53 33 20 

107 42 23

534422 

108 03 30

53 55 12 

108 24 36

54 07 22 

1084821

54 19 26 

109 12 24

54 25 07 

109 24 19

bathymetry was deep

174 171 134 168

499 499 -460 470 Failed to record dato

916 917 -840 873

886 935 -870 885

922 863 - 876 Multiple 

transducer returns

698 707 -650 - Close to submarine 

scarp -460 m deep

263 269 - - Failed to record data

5 - Line OBS1A - Central Basin

52 52 24 

107 09 10

52 59 53 

107 27 23

53 13 41 

108 01 55

53 25 55 

108 32 50

53 28 56 

108 40 19

53 31 59 

108 47 36

52 52 24 

107 09 08

52 59 56 

107 27 24

53 13 40 

108 01 54

53 25 58 

108 32 40

53 29 00 

108 40 20

53 31 59 

108 47 38

1496 1499 -1400 1418

1681 1386 -1585 1595

1712 1714 -1605 1630

1454 1452 -1200 - Map shows 

complicated bathy.

420 422 -390 -

41 41 30-60 -

Explanations:

1. Horizontal location was measured by GPS using Magellan Pro-1000. Accuracy is estimated to be ± 50 

m. Vertical location (lake level) was assumed to be 455 m a.s.l.

2. Water depth at deployment and retrieval was measured by the Titov's sonar NAL-10 (with a 

frequency of 25 KHz and a range of up to 2 km). The sonar displays water depth in meters which is

Baikal 92 DBS 15 OF-93-7
calculated using the acoustic velocity of sea water (1500 m/s). The sonar has not been calibrated for 

at least 2 years and is probably accurate to within 5%.

3. Water depth from map refers to water depth from 1:300,000 Russian navigation charts of Lake 

Baikal.

4. Water depth from ranging refers to the azimuthal distance measured from an EG&G SeaLink 

transducer to the OBS at the sea floor. The range is corrected for fresh water velocity (~1440 m/s). 

The transducer was lowered to ~3 m below sea surface and the range was taken when the ship was 

stationary at the coordinates of deployment.

Baikal 92 OBS 16 OF-93-7
APPENDIX 3

Universal Time

Deployment 2 - Line OBS1 - Recording time 9/8 12:00 - 9/10 00:00

OBS time deployed hove to time time spotted 

station released on surface

OBSC4 9/720:25 9/10-- -- 17:55 17:58

OBS A3 9/720:52 9/1014:47 14:57 15:19

OBSA1 9/801:26 9/1009:55 23:55 9/1100:18

OBSB1 9/804:38 9/1006:31 06:33 06:56

OBSA2 9/808:06 9/1003:24 03:25 03:41

OBSC1 9/808:11 9/1001:00 01:01 01:05

OBSC9 9/810:34 9/1000:24 00:24 00:31

time retrieved 

on board Comments

18:04

15:38

00:24 Abandoned site at 12:30;

returned to site at 23:05

06:57

03:45

01:09

00:35

Deployment 3 Line OBS2- Recording time for OBS Cl, Al, A2, A3 9/13 07:00 9/14 19:00

Line OB S3 - Recording time for OBS Bl, C4, C9

OBSB1 9/1214:11 9/1511:18 11:19 11:28

OBS Cl 9/12 16:38 9/14 00:02 00:02 00:05

OBS Al 9/12 17:55 9/14 23:30 23:42 9/15 00:07

OBS A2 9/12 19:07 9/15 09:49 09:49 09:59

OBS A3 9/1220:37 9/1503:02 03:09 03:18

OBSC4 9/1222:35 9/1507:52 07:53 07:58

OBSC9 9/1223:55 9/1503:28 03:29 03:31

Deployment 4 - Line OBS4- Recording time 9/16 15:00 - 9/18 03:00

OBSC4 9/1600:04 9/1811:19 11:20 11:22

OBS C9 9/16 00:40 9/18 10:34 10:36 10:43

OBSA1 9/1603:50 9/1808:33 08:34 08:47

OBSA2 9/1605:58 9/1804:26 06:28 06:39

OBS A3 9/1607:57 9/1803:18 04:00 04:15

OBSB1 9/1609:55 9/1801:01 01:03 01:12

OBS Cl 9/16 10:56 9/17 23:50 23:52 23:55

Deployment 5 - Line OBSlA - Recording time 9/20 18:00 - 9/22 06:00

OBS A3 9/2009:21 9/2209:11 09:19 09:34

OBSA1 9/2010:46 9/2205:42 07:15 07:38

OBSB1 9/2013:26 9/2202:29 02:33 02:57

OBSA2 9/2015:50 9/2123:03 23:05 9/2200:01

OBS C4 9/20 16:29 9/21 22:02 22:02 22:07

OBSC1 9/2017:05 9/2121:11 21:12 21:13

- 9/13 13:00- 9/15 01:00

11:45

00:10

00:11

10:05

03:22

08:03

03:35

11:27

10:46

08:50

06:46

04:21

01:16

23:59

09:37

07:42 Release problem, alleviated by

lowering transducer to -12 m

03:01

00:04

22:18

21:20

Baikal 92 OBS 17 OF-93-7
APPENDIX 4

Balkhash navigation and source information

Navigation on the Balkhash was based on an Ashtech GPS Receiver model XII. The location 

of the Ashtech antena was 28.5 m forward of the stern of the ship. The distance from the ship's stern 

to the center of the airgun array was 25 m. The distance to the two large guns was 50 m. The airgun 

array was towed at a depth of 6 m, and the two large guns were towed at a depth of 25 m.

Shot-instance information was initiated via a hydrophone in the gun array and transmitted 

as a 5 volt pulse to the navigation computer where is was recorded together with shot location.

OBS Lines 1 (Central Basin) and 4 (Northern Basin) were shot with two 60 liter airguns (total 

of 7320 cu. in.). These guns were fired at a two minute interval with a pressure of 1600-1700 psi. 

Average ship's speed during these lines was 4-4.1 knot resulting in nominal shot spacing of about 240 

m. An attempt was made to tune the pulse by introducing a delay of 40-60 msec between the firing of 

the two guns. The first 1.5 hours of shooting Line 1 was spent adjusting the delay.

OBS Lines 2 (across Academician Ridge) and 1A (the northern part of Line 1) were shot with 

a tuned array of 10 airguns with a total volume of 27.3 liter (1665 cu. in.) and pressure of 1900-2000 

psi. The airguns were sleeve-type guns built in Russia. They were divided into three clusters and 

towed from two points at the fan tail, port and starboard. Shot spacing was 50 m. During Line 2 the 

ship sailed at 4-4.4 knots and fired at intervals of 23-25 seconds. During Line 1A the ship sailed at 

3.75 knots and fired at interval of 27 seconds. Further source and navigation information is detailed in 

Nichols et al. (1993).

Line

OBS-1 

OBS-1*

OBS-2/ 

MCS 92-46

OBS-4/ 

MCS 92-17A

OBS 1A/ 

MCS 92-13

start 

ID/time

252/1230 

253/2210

257/0812

260/1506

264/1941

end 

JD/time

253/2140 

254/0008

257/1603

261/1210

265/1349

course 

(deg.)

054 

236

325

229

237

length 

(km)

shot 

noints

244.2 1-986 

14.0 1001-1061

61.0

163.9

137.3

1-1180

5-641

1-2589

start 

position

52.279397 

105.764838 

53.510205 

108.741602

53.251878 

108.376358

54.434412 

109.436113

53.501733 

108.722485

eni 

position

53.518203 

108.76158 

53.440452 

108.565840

53.700253 

107.846888

53.454992 

107.572212

52.816503 

107.016140

Baikal 92 OBS 18 OF-93-7
* Upon arrival at the northern end of Line 1, the Balkhash turned around and repeated the line 

southward until the recording window on the OBSs ended.

Other MCS lines shot during which OBSs were recording: 

MCS 92-21 257/1651 257/2235 173

MCS 92-15 261/1925 262/0908 040

MCS 92-36 265/1551 265/1918 140

MCS 92-34 265/2111 266/0139 319

MCS 92-32 265/0335 265/0704 139

46.2 1-839 53.666790 53.254498

107.792267 107.878360

107.9 1-2055 53.345518 54.083445

107.837772 108.898247

28.2 1-525 52.849025 52.654285

107.015898 107.283753

35.0 1-680 52.625468 52.862920

107.138132 107.797945

26.7 1-515 52.768828 52.587982

107.716980 107.976357

Baikal 92 OBS 19 OF-93-7
APPENDIX 5

OBS performance

A total of five deployments were carried out during the experiment. On the first deployment 

OBS A-3 had a failure in it's release prior to deployment. Since the lake bathymetry required the 

use of large spheres, The release electronics from OBS C-3 was installed in OBS A-3. This meant that 

7 OBS's were available for deployment. No other problem were encountered in this deployment. 

Shooting of the line did not occur because of bad weather, so the instruments were retrieved and 

redeployed as quickly as possible. The line was shot on the second attempt. OBS C-l was deployed 

late due to repair problems in its release (a broken ground wire). On recovery OBS C-4 had no data 

because of a hard disk failure, and OBS B-l had no data because of an Analog-to-Digital converter 

failure. OBS A-l require repair of its release circuitry before it could be redeployed. Lines 2 and 3 

were deployed at the same time. Unfortunately, line 3 was never shot. All instruments worked 

without problems. In deploying line 4, OBS C-9 had severe release problems. Since it appeared that 

the chances for recovery were good, this OBS was deployed anyway. The line was shot, and all seven 

OBS's were recovered. OBS C-9 failed to record any data as the air test of the release prior to 

deployment caused a power loss which scrambled the dataloggers memory, losing any programming. 

OBS C-l failed to record any data because the connector of the oscillator became dislodged. The 

deployment operations were done by hand using a block and tackle. On this occasion, the line slipped 

and the OBS hit the water hard, dislodging the oscillator. OBS C-9 could not be repaired, so it was 

retired from service. OBS B-l had its hydrophone damaged during recovery (it was replaced by a 

spare unit). OBS A-l would indicate that it had released when it had not actually released. This 

turned out to be a frozen bearing on the release clevis which was repaired. It was necessary to 

reprogram the OBS's three times before line 1A was actually deployed. Eventually six OBS's were 

deployed, the line was shot, and all six OBS's were recovered. All instruments worked without 

problems.

Summary of failed or damaged equipment, which need repair: 

2 Releases (for OBSs A3 and C9). 

1 hydrophone. 

1 battery pack. 

1 hard disk.

Baikal 92 OBS 20 OF-93-7
APPENDIX 6

Ship's operation

The R/V Titov, named after the second Soviet cosmonaut, General German Stepanovitch 

Titov, Hero of the Soviet Union, is a converted fishing boat with a length of 25 m, width of 5 m, 

drought of 2 m, and a 137 metric tonne displacement. The ship is owned and operated by the 

Limnological Institute of the Siberian Branch of the Russian Academy of Science. The age of the ship 

is unknown but she has been in dry dock for the last five years being rebuilt and refitted for science. 

This OBS experiment was her maiden voyage. Most of the ship's systems performed well although 

the sixth deployment had to be cancelled because of a problem with the ship's main generator.

The ship was only minimally suitable for the OBS work and for a long cruise. The only lab 

space was below deck and accessed through a steep and narrow staircase and a long and narrow 

corridor. Since there was no way to lower the OBS below deck, a plywood shack was built on deck. 

The shack covered the only open space on the deck, measuring 2.5 meters by 3 meters. Two doors were 

built to accommodate the transfer of an OBS inside the lab. The shack had no floor and was flooded 

when seas were rough or when the deck was washed. The plywood boards were peeling off layers of 

wood as the cruise proceeded. The structure was held by nails that were driven in at the top of each 

corner, and ropes were attached from each nail to some fixture on the boat. The ropes helped to keep 

the box on the deck and kept the box from twisting excessively. A sheet of tarp was tied to the roof to 

prevent rain from entering the shack. Inside there were two benches. A small one held the 

dataloggers and a power supply to keep them powered. The other bench held the computer, GPS 

clock, frequency counter, and the oscilloscope. A VHP radio for communication with the other ship 

was mounted on the wall. The release deck equipment was stored under the large bench. Two plastic 

shipping cases were used to keep the batteries and other expendables dry. With an OBS was 

dismantled inside, there was enough room for two people, as long as they were on friendly terms. The 

shack was nicknamed the "Winter Palace" for its Spartan accommodation and noticeable lack of 

heat. Work on the OBS under these conditions was difficult. In addition, the ship could not operate 

under rough weather for fear that the shack would blow away.

The ship has a forward deck cluttered with winches, a life boat, and various entries and 

covers to spaces below deck. With the shack, and the anchors, and OBSs on deck, there was little 

room left for movement during deployment and retrieval. Out of 5 winches located on deck, only one 

was functional and it was located forward were deployment was impossible. All overboard 

operations were therefore, carried out by hand using a block and a tackle tied to a boom above the 

center of the boat. The OBS's anchors had to be strategically located all over the ship to avoid any

Baikal 92 OBS 21 OF-93-7
significant list. At the beginning of the expedition, the ship had a bad roll moment from all of the 

weight sitting high on the deck. This situation improved as the anchors were used up. After each 

line was deployed, the anchors had to be relocated to redistribute the weight. Security at the dock 

was a serious problem. Guards were either unavailable or unreliable, and theft was common. This 

meant that mobilization had to be done all at once, and, once loaded, someone had to remain with the 

ship at all times.

The crammed living quarters, crowded deck, and small lab were inadequate for a 25tiay cruise 

with 13 people on board. Fortunately, frequent port and beach stops eased the crowding. 

Additionally, the ship's crew was extremely helpful and considerate and kept the ship in good 

sanitary conditions. The professionalism and enthusiasm of the ship's captain and crew compensated 

for the difficult conditions and assured smooth and rapid deployment and retrieval of the OBSs.

Baikal 92 OBS 22 OF-93-7
APPENDIX 7

Power limitations

In specifying the equipment and supplies for this operation, consideration was made for 

power, timing accuracy, archiving the acquired data, and general deployment and maintenance parts. 

The power available on Russian vessels is 220 volts 50 Hertz. Some of the newer vessels use a threewire system with the lower pin tied to ground, but most use the standard two-wire system with one 

hot wire and a neutral. Neutral is not tied to ground and can be as much as 150 volts above ground. A 

grounding network of all pieces of equipment are tied together and then connected to the ship's hull to 

alleviate any electrical hazard. After installation of the equipment on the ship, any signal grounds 

on the equipment are also checked and tied to earth ground if necessary. To provide power to the 

electronics, one primary and two backup systems were used. The primary system uses a 2.2 Kilowatt 

uninterruptable power supply (UPS) to convert the 220 volt 50 Hertz to 110 volts 60 Hertz. The UPS 

was modified to eliminate the bypass operation. The circuit that charges the DC battery supply was 

set for an input of 220 volts 50 Hertz. The rectifier that converts the DC supply to AC is set for 110 

volts 60 Hertz. This system provides good isolation from spikes and provides battery backup for short 

term losses of power. The first backup power system is a 5 Kilowatt diesel-powered generator. 

Although the power output is twice the power needed, smaller units do not hold up as well under 24 

hour operations. The final backup system uses several 1500 watt 220 to 110 volt transformers. This 

method requires that all of the equipment operate at 50 Hertz.

Providing power for the equipment also proved difficult. The multichannel ship (Balkash) 

utilized a 6 kW UPS system with an 8 kW generator as backup to power the electronics. The UPS 

system failed on the first day, and the generator was too large to load onboard the ship. The 2.2 kW 

UPS system (the primary power for the OBS operations) was used to power the multichannel 

electronics. The UNIX-based computers used to de multiplex the multichannel data had no power 

available, so the OBS generator was used to power these systems. This meant that both primary and 

backup power options for the OBS were no longer available, and the Titov's generators had to be used 

as the only source of power. The GPS clock, frequency counter, and oscilloscope were modified to 

operated using 220 volts 50 Hertz. The rest of the electronics were powered using 2, 1500 watt 220 to 

110 volt transformers. Because of the wattage limitations, the Rb standard was not used in this 

operation. Grounding problems still existed even though each piece of electronics was tied to earth 

ground. The acoustic release electronics performed the poorest of all of the electronics. The external 

power supply used to power the electronics could not adequately filter out the noise generated by the 

ship's power. As a result, the receiver circuits were useless. The transmitter worked well, so all 

release operations were done by transmitting the release signal and assuming that the OBS did

Baikal 92 OBS 23 OF-93-7
release. This procedure did not always work well, as the lake had a strong thermocline that made it 

occassionally necessary to make many attempts for each release.

Baikal 92 OBS 24 OF-93-7