Submarine Crash Shows Navy Had Gaps in Mapping System

Sailors on the San Francisco, a nuclear-powered attack submarine, had just finished cleaning the vessel last Saturday as it sped along 500 feet beneath the surface of the South Pacific. Submarines run blind, just listening for sounds of danger. And to the captain and other officers relying on undersea navigation charts, everything seemed clear.

Suddenly, there was a horrible screeching. And according to an e-mail message written by a crew member, the inside of the submarine quickly resembled a scene from the movie "The Matrix." He wrote, "Everything slowed down and levitated and then went flying forward faster than the brain can process."

The submarine had crashed head-on into an undersea mountain that was not on the charts. One sailor was killed, and about 60 others were injured. Now, Defense Department officials say they have found a satellite image taken in 1999 that indicates an undersea mountain rising to perhaps within 100 feet below the surface there.

But the older navigation charts provided to the Navy were never updated to show the obstruction, they acknowledge, in part because the agency that creates them has never had the resources to use the satellite data systematically.

The officials said the main chart on the submarine, prepared in 1989 and never revised, did not show any potential obstacles within three miles of the crash. They said the incident happened in such a desolate area - 360 miles southeast of Guam - that updating their depiction of the undersea terrain was never considered a priority.

The new information about the charting flaws also illustrates what many experts say is a broader danger not only to submarines but also to many surface ships. At the same time, it provides a glimpse into the arcane task of plotting an undersea world that in some areas is still more mysterious than the surfaces of Mars or Venus.

A variety of satellite data is now showing that many sea charts, including some that still rely on notations from the days when sailors navigated by the stars, are inaccurate. And some scientists are calling for greater use of satellite data to fix more precisely the location of undersea ridges, islands and even continental boundaries and to chart large, less studied areas of the oceans.

The latest disclosures support the account by the commanding officer of the San Francisco that the charts showed that his track was clear. But former submarine captains said Navy investigators were likely to examine whether it had been prudent to travel at such a high speed, 30 knots, given the age and spottiness of the information.

Officials said the main chart on the submarine was prepared by the Defense Mapping Agency in August 1989. That office was later absorbed into the National Geospatial-Intelligence Agency, a part of the Defense Department that provides maps, sea charts and other geographic intelligence to the nation's combat forces.

Chris Andreasen, the chief hydrographer for the Office of Global Navigation at the intelligence agency, acknowledged in an interview that on the chart, "there's nothing shown that would be a hazard" at the crash site.

But since the accident, Mr. Andreasen said, his office has examined commercially available images taken by a Landsat satellite in 1999, and at least one image indicates that an undersea mountain could rise to within 100 feet of the surface there. Analysts say variations in water color can sometimes indicate a land mass below.

Mr. Andreasen said his agency had not normally used satellite imagery to update sea charts, though it recently began using the images to help pinpoint the boundaries of islands and other land masses. He and other officials said that the charting office's staff had shrunk in recent years, and that the Navy never asked it to focus on the area south of Guam, where it began basing submarines in 2002.

Current and former Navy officials say the main focus during the cold war was charting areas in the Northern Pacific and in Arctic seas where missile and surveillance submarines guarded against a Soviet attack. Since then, the Navy has been trying to improve charts of shallower coastal waters in the Middle East and other areas where it might have to help battle terrorists.

Mr. Andreasen said that since global positioning satellites came into wide use in the 1980's, Navy and commercial ships had had a much more accurate way to fix the coordinates of islands, undersea volcanoes and other parts of the giant mountain ranges that jut up from the ocean floor.

As ships have reported these coordinates, sea-charting offices around the world have found that many islands were "maybe a mile or two out of position" on widely used charts, he said. So over the past year, his agency has been using the Landsat images and other data to update many nations' boundaries.

But Mr. Andreasen and other scientists said that while commercial shipping interests had helped chart the most common transit routes, large areas of the ocean depths remained little charted.

Dr. David T. Sandwell, a geophysics professor at the Scripps Institution of Oceanography in San Diego, said that about 40 percent of the oceans were "very, very poorly charted, and those areas are mostly in the Southern Hemisphere."

While many sea charts include obstacles and features spotted by commercial vessels, World War II warships and even 19th-century explorers, the best charts are made by survey ships that use sound beams to create detailed pictures of the undersea terrain. The Navy has only seven such ships, however, and scientists say it could take decades to chart the rest of the seas thoroughly.

As a result, Dr. Sandwell and others have suggested that the government make rough chartings of more areas with another type of satellite - one that uses radar to measure variations in the height of the ocean that can signal if mountains are below.

Dr. Sandwell said readings by one such satellite in the mid-1980's also indicated there could be an undersea mountain at the San Francisco's crash site. But he said the margin of error was too large for the studies to be conclusive. And Mr. Andreasen said much of the satellite data was too vague for precise charting.

Mr. Andreasen said the main chart used on the submarine showed that the only concerns were a small area of discolored water that had been noted three miles from the crash site and some coral reefs about 10 miles away.

Notes on the chart indicated that the discolored water was mentioned on a British sea chart in 1963, and Mr. Andreasen said the notation might even go back to World War II. He said the discoloration might have been just a temporary disturbance, or it could have been a sign of the undersea ridge.

Other notes suggest that some ships had reported depths of 5,000 to 6,000 feet nearby. But Mr. Andreasen said few commercial ships used the area, and "it has never been systematically surveyed."

The submarine left Guam on Jan. 7 for Brisbane, Australia. The Navy said 23 of the sailors were seriously injured, and at least five had broken bones.

The e-mail message by the sailor was sent to several people involved with submarines, and as it circulated within the submarine community, one person provided a copy to The New York Times.

The sailor wrote that many crew members were eating lunch at the time of the crash, which severely damaged the vessel's bow. He said several sailors suffered "bad head wounds," and men in the engine room smashed against "lots of metal and sharp edges."

Still, he said that the vessel's damage control party "did everything exactly right even though they were hurt as well."

The message also said that the submarine was lucky to have an extra medic on board, and that its main medic, known as a corpsman, did not sleep during the two-day trip back to port.

The Navy has said a machinist's mate second class, Joseph A. Ashley of Akron, Ohio, was knocked unconscious by the crash and died the next day from severe head injuries. The e-mail message said other sailors were surprised that the corpsman "got him to hold on as long as he did."

From an earlier thread:

U.S.S. San Francisco preparing to dock at Apra Harbor

posted Jan 10, 2005.

We have this:

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To: BigSkyFreeper

I've heard of flying into a mountain -- but not doing so underwater...

The crazy thing about the topography of the ocean floor in that area is that the seamounts of the Caroline Ridge (which the sub supposedly hit) are very near to the Marianas Trench -- the deepest spot on Earth...

My guess is that our undersea topographic mapping in this area is not too good.

3 posted on 01/09/2005 11:43:10 PM PST by TXnMA (Attention, ACLU: There is no constitutionally protected right to NOT be offended -- Shove It!)

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To: TXnMA

Found this, seems to be a very interesting area.

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Introduction

The Yap Trench lies on the southeastern boundary of the Philippine Sea Plate in the western Pacific (Fig. 1). The Yap Trench is one section of a continuous system of arcuate trenches. These include the Izu-Bonin, Mariana, Yap, and Palau trenches, framing the eastern boundary of the Philippine Sea Plate. The Yap Trench is in a complex tectonic region of convergence between the Philippine Sea, the Pacific, and the Caroline plates. The Yap, Palau trenches, and the Ayu Trough, which is located in the southwest of the Palau Trench, form a plate boundary between the Philippine Sea and the Caroline plates. The Yap and Palau trenches are considered to be convergent boundaries, while the Ayu Trough is thought to be a divergent boundary (Weissel and Anderson, 1978; Fujiwara et al., 1995). Models of Philippine Sea Plate motion (Ranken et al., 1984; Seno et al., 1993) indicate that the rotation pole of the Philippine Sea-Caroline plates is at the junction of the Palau Trench and Ayu Trough, near 6°N, 134°E. The rate of relative plate motion is estimated to be 0.7°/m.y., that is, 0-6 mm/yr along the Yap and Palau trenches (Seno et al., 1993). The age of the subducting West Caroline Basin of the Caroline Plate is estimated to be 35°30 Ma (Bracey, 1975; Hegarty and Weissel, 1988; Yamazaki et al., 1994), and the age of the overlying Parece Vela Basin of the Philippine Sea Plate is estimated to be 30°25 Ma (Mrozowski and Hayes, 1979).

Fig.1:
Location map of the Yap Trench. The contour interval is 2,000 m. The box shows the survey area as shown in Fig.3. The distribution of earthquake hypocenters are represented by solid black symbols: Circles = source depth shallower than 50 km, Diamonds = 50-100 km, Crosses = deeper than 100 km. Global hypocentral data from ISC since 1980. fig.1:

Fig.2:

Bathymetric map of the circumambient regions of the Yap Trench. The contour interval is 500 m. The bathymetric data are based on the global bathymetry of ETOPO5 (NGDC, 1988). The star symbol shows the pole position of Philippine Sea - Caroline plates estimated by Seno et al. (1993). The solid black symbols show hypocentral distribution. See Figure 1 caption.

The length of the Yap Trench is about 700 km (Fig. 2). The trench axis elongates in a convex shape toward the southeast. An arc involving the Yap Island on the Philippine Sea Plate side forms a trench-arc system. This arc consists primarily of metamorphic rocks and lacks active volcanism (Shiraki, 1971; Hawkins and Batiza, 1977). The arc-type rocks found on the islands are no younger than Late Oligocene or Miocene. The distance between the island-arc and the trench axis is about 50 km, which is much less than that of other trench-arc systems. The Caroline Ridge, oriented in an ESE-WNW direction, intersects the trench from the east. This ridge consists of a chain of seamounts thought to be of hotspot origin (Keating et al., 1984) of less than 40 m.y. (Hegarty and Weissel, 1988). Seismicity along the trench is low. Earthquakes occur at a depth of less than 50 km, and no deep-focus earthquakes are apparent along the trench. A Wadati-Benioff zone, demonstrated by a plane of deep-focus earthquakes reflecting dynamic interaction between a subducting and an overriding plates, is thus not defined. Considering the above geological and geophysical features, the Yap Trench is controversial regarding the activity of plate subduction at present. Hawkins and Batiza (1977) and McCabe and Uyeda (1983) suggested that subduction at the Yap Trench may have suspended by collision of the Caroline Ridge. McCabe and Uyeda (1983) suggested that the Caroline Ridge collided with the Yap Trench in early Miocene, and that this collision made the volcanic activity in the Yap Arc stop, and narrowing the distance between arc and trench. In contrast, some petrological and geophysical studies suggested that subduction at the trench may still be active. Fresh volcanic rock fragments and hydrothermally affected rocks, dredged in the back-arc region, may suggest in-situ or nearby hydrothermal activity in relation to Quaternary volcanic activity (Fujioka et al., 1986). High heat flow values were observed in the back-arc region and appreciably large values of negative free-air gravity anomalies were observed along the trench axis (Nagihara et al., 1989). Large negative gravity anomaly is indicative of dynamic force exerted on crust under the trench associated with ongoing subduction of the oceanic lithosphere. Observation of micro-seismic activity in the trench area suggested that tectonic force, found in active subduction zones, acted on the crust of the trench (Sato et al., 1997).

Prior to our study, there were insufficient data for understanding the tectonics and geodynamics of the Yap Trench. We conducted swath bathymetry and gravity surveys of the Yap Trench aboard the R/V Yokosuka in 1993, 1994 and 1996, in combination with dive surveys of the research submersible Shinkai 6500 (Fujioka et al., 1994, 1996). We hope that our study stimulates further geological and geophysical studies in this region, focused on morphotectonic characteristics, by providing a high quality base map, and that it will provide insight into the tectonics of the Yap Trench, the Philippine Sea Plate and the circum-plates.

Diagrams :

here

4 posted on 01/09/2005 11:59:45 PM PST by Ernest_at_the_Beach (A Proud member of Free Republic ~~The New Face of the Fourth Estate since 1996.)

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To: All

5 posted on 01/10/2005 12:02:16 AM PST by Ernest_at_the_Beach (A Proud member of Free Republic ~~The New Face of the Fourth Estate since 1996.)

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To: All; BigSkyFreeper

Survey ship tracks in the region of the Yap Trench. The solid, gray and dashed lines show the tracks from the Y95-06, Y96-12, and Y93-03 cruises of the R/V Yokosuka, respectively. The dotted lines show the tracks of the KH92-1 cruise of the R/V Hakuho-maru. The area surveyed by Iwabuchi et al. (1990) aboard the S/V Takuyo is stippled.

Looks like this survey was concerned aout mapping the deep trench areas..

No interest in the Seamount areas.

6 posted on 01/10/2005 12:06:49 AM PST by Ernest_at_the_Beach (A Proud member of Free Republic ~~The New Face of the Fourth Estate since 1996.)

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