(Adds quarterly data, context)
RIO DE JANEIRO, Nov 18 (Reuters) - Economic activity in Brazil contracted for the fourth straight quarter, central bank data showed on Wednesday as Latin America's biggest economy plunges further into recession.
The central bank's IBC-Br economic activity index indicates economic activity fell 1.41 percent in the third quarter from the previous three months. That follows contractions of 2.09 percent in the second quarter, 1.05 percent in the first and 0.50 percent in the last quarter of 2014.
The IBC-Br, a gauge of activity in the farming, industry and services sectors, fell 0.5 percent in September from the prior month.
The median forecast in a Reuters survey of 18 analysts was for a 0.60 percent decline in the indicator.
The IBC-Br index is an early indicator of gross domestic product data. The IBGE, the national statistics institution, is scheduled to release third-quarter GDP data on Dec 1.
Activity fell 6.2 percent in September from a year earlier, the steepest of a series of declines that started almost a decade ago.
"It's clear that the recession deepened in the third quarter and the fall in output was steeper than the 2.6 percent year-on-year decline suffered in the second quarter," Capital Economics analyst Edward Glossop said in a research note.
Glossop said activity probably continued to fall at the start of the fourth quarter as industrial output plummeted and rising unemployment likely hit consumption.
Brazil's economy has slipped into its worst recession in 25 years, hit by high inflation, rising interest rates and a string of tax hikes and spending cuts by President Dilma Rousseff. Independent economists expect the economy to contract 3.10 percent this year.
Economists also expect activity to contract next year in what would be the longest recession in Brazil since the Great Depression of the 1930s. (Reporting by Stephen Eisenhammer and Alonso Soto; Editing by Toby Chopra and Lisa Von Ahn)