A massive undersea current and earthquakes on the floor of the Pacific Ocean may be related to the El Nino, a periodic climate change that can disrupt weather around the world, according to a pair of new studies.

Scientists at the National Oceanic and Atmospheric Administration reported Thursday that the huge current flowing beneath the surface of the Pacific may have signaled the end of the 1986-87 El Nino.The American Geophysical Union, meanwhile, published a report, which it acknowledged was controversial, disclosing an apparent relationship between El Nino and seafloor earthquakes.

The term El Nino refers to a complex series of atmospheric and ocean events that occur every two to seven years. It attracted widespread attention in 1982-83 when the phenomenon disrupted weather patterns around the world. It was eventually blamed for 1,500 deaths and damage ranging from $2 billion to $8 billion.

That, however, was the strongest El Nino of this century. Most fit the much milder pattern seen in 1986-87, when some weather changes were noted, but little major damage was done.

The disruptions of 1982-83 included a worsening of Africa's deadly drought, severe winter storms in California, reduced fish catch in South America, Australia's worst drought in 200 years, heavy rainfalls in Peru and Ecuador and the first typhoon to hit French Polynesia in 75 years - followed by five more in five months.

Scientists measure the arrival and departure of an El Nino (pronounced el-neen-yo) by changes in ocean surface temperatures along the west coast of South America and changes in the air pressure differential between northern Australia and the central or eastern Pacific.

Falling air pressure at Easter Island tends to be a good indicator of an El Nino, according to an analysis by Daniel A. Walker of the University of Hawaii.

His findings, reported in the American Geophysical Union's weekly periodical "Eos," found a correlation between that air pressure drop and increases in seafloor earthquakes in the Easter Island region.

The article was "published with our recognition that it presents controversial material. . . . Even the possibility of linkages here should be of interest to both geophysicists and oceanographers," wrote Eos oceanography editor Robin D. Muench.

Increased earthquake activity occurred at about the same time as the El Ninos of 1965, 1976-77 and 1986-87 and just ahead of the El Ninos of 1972-73 and 1982-83, Walker found.