The β-decay of the even-even nucleus <sup loc="post">70</sup>Kr with <math altimg="si1.svg"><mi>Z</mi><mo linebreak="goodbreak" linebreakstyle="after">=</mo><mi>N</mi><mo linebreak="goodbreak" linebreakstyle="after">+</mo><mn>2</mn></math>, has been investigated at the Radioactive Ion Beam Factory (RIBF) of the RIKEN Nishina Center using the BigRIPS fragment separator, the ZeroDegree Spectrometer, the WAS3ABI implantation station and the EURICA HPGe cluster array. Fifteen γ-rays associated with the β-decay of <sup loc="post">70</sup>Kr into <sup loc="post">70</sup>Br have been identified for the first time, defining ten populated states below <math altimg="si2.svg"><msub><mrow><mi>E</mi></mrow><mrow><mi mathvariant="normal">exc</mi></mrow></msub><mo linebreak="goodbreak" linebreakstyle="after">=</mo><mn>3300</mn></math> keV. The half-life of <sup loc="post">70</sup>Kr was derived with increased precision and found to be <math altimg="si3.svg"><msub><mrow><mi>t</mi></mrow><mrow><mn>1</mn><mo stretchy="false">/</mo><mn>2</mn></mrow></msub><mo linebreak="goodbreak" linebreakstyle="after">=</mo><mn>45.19</mn><mo>±</mo><mn>0.14</mn></math> ms. The β-delayed proton emission probability has also been determined as <math altimg="si4.svg"><msub><mrow><mi>ε</mi></mrow><mrow><mi mathvariant="normal">p</mi></mrow></msub><mo linebreak="goodbreak" linebreakstyle="after">=</mo><mn>0.545</mn><mo stretchy="false">(</mo><mn>23</mn><mo stretchy="false">)</mo><mtext>%</mtext></math>. An increase in the β-strength to the yrast 1<sup loc="post">+</sup> state in comparison with the heaviest <math altimg="si1.svg"><mi>Z</mi><mo linebreak="goodbreak" linebreakstyle="after">=</mo><mi>N</mi><mo linebreak="goodbreak" linebreakstyle="after">+</mo><mn>2</mn></math> system studied so far (<sup loc="post">62</sup>Ge decay) is observed that may indicate increased np correlations in the <math altimg="si5.svg"><mi>T</mi><mo linebreak="goodbreak" linebreakstyle="after">=</mo><mn>0</mn></math> channel. The β-decay strength deduced from the results is interpreted in terms of the proton-neutron quasiparticle random-phase approximation (pnQRPA) and also with a schematic model that includes isoscalar and isovector pairing in addition to quadrupole deformation. The application of this last model indicates an approximate realization of pseudo-SU(4) symmetry in this system.< Réduire