The amplitude and phase of the cosmic-ray anisotropy are well established experimentally between 10 11 eV and 10 14 eV. The study of their evolution in the energy region 10 14-10 16 eV can provide a significant tool for the understanding of the steepening ("knee") of the primary spectrum. In this Letter, we extend the EAS-TOP measurement performed at E 0 ≈ 10 14 eV to higher energies by using the full data set (eight years of data taking). Results derived at about 10 14 and 4 × 10 14 eV are compared and discussed. Hints of increasing amplitude and change of phase above 10 14 eV are reported. The significance of the observation for the understanding of cosmic-ray propagation is discussed.

A. S. 1)6Au=uIN(**), V. G. RYASSNY(**), 0. G. RYAZHSKAYA(**), 0. SAAVEDRA(*), V. P. TALQCHEIN(**), G. TRINCHERO(*), S. VERNE~TO(*), G. T. ZATSEPIN(**) and V. F. YAKUSHEV(**) (*) Istituto di C o s m o g w f e del C.N.R.

We present the analysis of the muon events with all muon multiplicities collected during 21804 hours of operation of the first LVD tower. The measured angular distribution of muon intensity has been converted to the 'depth -vertical intensity' relation in the depth range from 3 to 12 km w.e.. The analysis of this relation allowed to derive the power index, γ, of the primary all-nucleon spectrum: γ = 2.78 ± 0.05. The 'depth -vertical intensity' relation has been converted to standard rock and the comparison with the data of other experiments has been done. We present also the derived vertical muon spectrum at sea level.PACS numbers: 13.85.T, 96.40.T

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